A156537 a(n), a(n+1), a(n+2), for n=2,5,8,11,... are respectively the numbers of representations of the integers 2^k-2, 2^k, 2^k+2, where k=(n+4)/3, by unordered sums of two numbers of A156284.

0, 0, 1, 1, 0, 1, 2, 0, 1, 2, 0, 3, 3, 0, 2, 5, 0, 4, 6, 0, 9, 19, 0, 8, 11, 0, 23, 51, 0, 27, 44, 0, 70, 207, 0, 80, 92, 0, 217, 399, 0, 279, 444, 0, 685, 1653, 0, 630, 1010, 0, 2137, 4893, 0, 3068, 3683, 0, 6855

Offset

2,7

Comments

According to the construction of A156284, a_(3n)=0, n>=1. These terms may be called "wells". The growth of the depth of the "wells" is O(2^(n/3)log(n)/n^2).

Links

Table of n, a(n) for n=2..58.

Crossrefs

Cf. A156284, A002375.

Sequence in context: A025666 A025679 A071491 * A239501 A145316 A137298

Adjacent sequences: A156534 A156535 A156536 * A156538 A156539 A156540

Keyword

nonn

Author

Vladimir Shevelev, Feb 09 2009, Feb 14 2009

Extensions

Edited by N. J. A. Sloane, Feb 14 2009

Additional terms from Vladimir Shevelev, Mar 19 2009

Status

approved