Table of n, a(n) for n=1..8.
First few terms of A137292 are 1,3,4,5,7,9,10,13,... . The first run of at least two consecutive numbers is 3,4; the first run of at least three consecutive numbers is 3,4,5. Hence a(2) = a(3) = 3.
Sequence in context: A292163 A242886 A221947 * A009011 A291095 A009498
Adjacent sequences: A138659 A138660 A138661 * A138663 A138664 A138665
Klaus Brockhaus, Mar 25 2008