Task: Formula-prediction-context (source dataset: pge-random)

You are given an table region extracted from a real Excel spreadsheet, which is centered around a cell called "Target Cell" (labeled as "[Target Cell]" shown in the table below). The table region below includes up to 10 rows above/below the Target Cell, and 10 columns to the left/right of the Target Cell. 

Your task is to analyze the table context surrounding the Target Cell, and predict the most likely Excel formula that should go in the Target Cell. If multiple formulas are possible, choose the most reasonable or commonly used based on context.

1. Please follow the standard formula syntax in Excel, e.g. always begins with an equal sign (=).
2. Base your predicted formula on the surrounding table context, e.g., column headers, annotations, and data values in nearby cells.
3. No explanation — just output the formula itself in a JSON format: {"formula": "your_formula_here"}.

Input Excel Snippet in Markdown format:
|    | A   | B    | C   | D                                                        | E   | F                                                                 | G                                       | H      | I         | J                         | K                  | L       | M   | N   | O   | P   |
|---:|:----|:-----|:----|:---------------------------------------------------------|:----|:------------------------------------------------------------------|:----------------------------------------|:-------|:----------|:--------------------------|:-------------------|:--------|:----|:----|:----|:----|
| 21 |     |      |     |                                                          |     |                                                                   | 2016 and beyond (after Floor Test Term) |        | MHR       | Btu/kWh                   |                    |         |     |     |     |     |
| 22 |     |      |     |                                                          |     |                                                                   |                                         |        |           |                           |                    |         |     |     |     |     |
| 23 |     |      |     |                                                          |     |                                                                   |                                         |        |           | Market Heat Rate          | 8673.045216987033  | Btu/kWh |     |     |     |     |
| 24 |     |      |     |                                                          |     |                                                                   |                                         |        |           |                           |                    |         |     |     |     |     |
| 25 |     |      |     |                                                          |     |                                                                   |                                         |        |           |                           |                    |         |     |     |     |     |
| 26 |     | BTGP | =   | GPn + GTn   (Calendar month Burner Tip Gas Price), where |     |                                                                   |                                         |        |           |                           |                    |         |     |     |     |     |
| 27 |     |      |     |                                                          |     |                                                                   |                                         |        |           |                           |                    |         |     |     |     |     |
| 28 |     |      |     | GPn                                                      | =   | Simple average of natural gas bidweek price indices for Malin and |                                         | Malin  | 3.8817    | $/MMBtu                   |                    |         |     |     |     |     |
| 29 |     |      |     |                                                          |     | Topock from Gas Daily, Natural Gas Intelligence and Natural Gas   |                                         | Topock | 4.3717    | $/MMBtu                   |                    |         |     |     |     |     |
| 30 |     |      |     |                                                          |     | Week                                                              |                                         |        |           |                           |                    |         |     |     |     |     |
| 31 |     |      |     |                                                          |     |                                                                   |                                         |        |           | Average Bidweek Gas Price | [Target Cell]      | $/MMBtu |     |     |     |     |
| 32 |     |      |     |                                                          |     |                                                                   |                                         |        |           |                           |                    |         |     |     |     |     |
| 33 |     |      |     | GTn                                                      | =   | Intrastate Transportation                                         |                                         |        |           |                           |                    |         |     |     |     |     |
| 34 |     |      |     |                                                          |     |                                                                   |                                         |        |           |                           |                    |         |     |     |     |     |
| 35 |     |      |     |                                                          |     | G-AAOFF - Redwood                                                 | PG&E AL 4348-G                          |        |           |                           | 0.8753             | $/MMBtu |     |     |     |     |
| 36 |     |      |     |                                                          |     | G-AAOFF - Baja                                                    | PG&E AL 4348-G                          |        |           |                           | 1.0793             | $/MMBtu |     |     |     |     |
| 37 |     |      |     |                                                          |     | Gas Rule 21 Shrinkage                                             | PG&E AL 4381-G, Backbone                |        | Shrinkage | 0.012                     | 0.0501218623481785 | $/MMBtu |     |     |     |     |
| 38 |     |      |     |                                                          |     | Backbone Transport                                                | Average Redwood, Baja plus shrinkage    |        |           |                           | 1.0274             | $/MMBtu |     |     |     |     |
| 39 |     |      |     |                                                          |     |                                                                   |                                         |        |           |                           |                    |         |     |     |     |     |
| 40 |     |      |     |                                                          |     | G-EG*                                                             | PG&E AL 4440-G, Non-Backbone            |        |           |                           | 1.2289999999999999 | $/MMBtu |     |     |     |     |
| 41 |     |      |     |                                                          |     | G-SUR                                                             | PG&E AL 4454-G                          |        |           |                           | 0.0216             | $/MMBtu |     |     |     |     |



min_row: 21
max_row: 41
min_col: 1
max_col: 16
target_cell_row_idx: 31
target_cell_col_idx: 11
target_cell_value: 4.1267
formula: =ROUND(AVERAGE($I$28,$I$29), 4)