A339985 G.f.: g(x)^2 * g(x^2), where g(x) is the g.f. of A000081.

0, 0, 0, 0, 1, 2, 6, 14, 37, 90, 232, 584, 1512, 3906, 10246, 26984, 71766, 191852, 516400, 1396760, 3797435, 10367628, 28420466, 78183462, 215791426, 597368222, 1658233794, 4614679792, 12872125836, 35982713314, 100787606966, 282832173830, 795070060983

Offset

0,6

Links

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

Formula

a(n) ~ 2 * 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[g81^2 * g81x2, {x, 0, max}], x]

Crossrefs

Cf. A000081, A217781, A339984.

Sequence in context: A171924 A144530 A248113 * A026598 A006864 A217420

Adjacent sequences: A339982 A339983 A339984 * A339986 A339987 A339988

Keyword

nonn

Author

Vaclav Kotesovec, Dec 25 2020

Status

approved