There are no letters in that sequence. The progression of numbers can be
extended according to the rule shown by appending '26' as the fifth term.
16
16 is the next squared number.
16 21 22 29
2and1
The next numbers in the sequence are... 16, then 88.
The next number in the sequence 2, 4, 16, 64 is 256.
a
16
16 is the next squared number.
16 21 22 29
65,536 is.
8
It is: 34
2and1
7 10 16 28
The next numbers in the sequence are... 16, then 88.
191 and then 420.