Table:
text: IEEE 802.11b-1999
Channels and Frequencies
b 
 802.11 
 channel to frequency map
Channel Center_Frequency Frequency_delta Channel_Width Overlaps_Channels
1 2.412 GHz 5 MHz 2.401–2.423GHz 2-5
2 2.417 GHz 5 MHz 2.406–2.428GHz 1,3-6
3 2.422 GHz 5 MHz 2.411–2.433GHz 1-2,4-7
4 2.427 GHz 5 MHz 2.416–2.438GHz 1-3,5-8
5 2.432 GHz 5 MHz 2.421–2.443GHz 1-4,6-9
6 2.437 GHz 5 MHz 2.426–2.448GHz 2-5,7-10
7 2.442 GHz 5 MHz 2.431–2.453GHz 3-6,8-11
8 2.447 GHz 5 MHz 2.436–2.458GHz 4-7,9-12
9 2.452 GHz 5 MHz 2.441–2.463GHz 5-8,10-13
10 2.457 GHz 5 MHz 2.446–2.468GHz 6-9,11-13
11 2.462 GHz 5 MHz 2.451–2.473GHz 7-10,12-13
12 2.467 GHz 5 MHz 2.456–2.478GHz 8-11,13-14
13 2.472 GHz 5 MHz 2.461–2.483GHz 9-12, 14

Question: What is the channel width overlapping channels 1,3-6 for IEEE 802.11b-1999?