A339984 G.f.: g(x) * g(x^2), where g(x) is the g.f. of A000081.

0, 0, 0, 1, 1, 3, 5, 13, 26, 65, 147, 369, 899, 2298, 5851, 15261, 39945, 105948, 282504, 759480, 2052027, 5576017, 15216998, 41705762, 114715503, 316611401, 876466003, 2433091773, 6771462322, 18889829555, 52809592990, 147935027381, 415182991401, 1167251435240

Offset

0,6

Links

Vaclav Kotesovec, Table of n, a(n) for n = 0..2000

Formula

a(n) ~ A339986 * A051491^n / n^(3/2).

Mathematica

max = 30; A000081 = Rest[Cases[ Import["https://oeis.org/A000081/b000081.txt", "Table"], {_, _}][[All, 2]]]; g81 = Sum[A000081[[k]]*x^k, {k, 1, max}]; g81x2 = Sum[A000081[[k]]*x^(2*k), {k, 1, max}]; CoefficientList[Series[g81 * g81x2, {x, 0, max}], x]

Crossrefs

Cf. A000081, A217781, A309619, A339985.

Sequence in context: A026003 A103792 A076156 * A141630 A289467 A289533

Adjacent sequences: A339981 A339982 A339983 * A339985 A339986 A339987

Keyword

nonn

Author

Vaclav Kotesovec, Dec 25 2020

Status

approved