Best completes the sequence 1 3 7?

Answer 1

There are two possibilities.

• The sequence is 1, 3, 7, 15, 31, 63.....
• The sequence is 1, 3, 7, 13, 21, 31......

It depends on whether the difference from one number to the next is doubled (i.e., 2, 4, 8, 16, 32, etc), or if two is simply added each time to arrive at the next stop in the sequence (i.e., 2, 4, 6, 8, 10, etc). There could also be other sequences, but there is simply not enough of the original sequence to know exactly what was originally intended.