lower previous curve by 1.

Here are attempts so far:

  orig take1 take2 take3 take4 forTake5
0     3     3     5     5     5        4
1     3     3     5     5     5        4
2     4     4     6     6     6        5
3     5     5     8     8     8        7
4     6     6    11    11    10        9
5     8     8    14    14    12       11
6    10    10    18    18    15       14
7    12    12    22    22    18       17
8    15    16    26    26    22       21
9    18    19    31    30    26       25
10   21    22    37    34    30       29
11   25    26    43    38    35       34
12   29    30    50    42    40       39
13   33    34    57    46    45       44
14   37    38    64    50    51       50
15   42    43    72    54    57       56