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%I #6 Dec 26 2020 02:48:39
%S 0,0,0,0,1,2,6,14,37,90,232,584,1512,3906,10246,26984,71766,191852,
%T 516400,1396760,3797435,10367628,28420466,78183462,215791426,
%U 597368222,1658233794,4614679792,12872125836,35982713314,100787606966,282832173830,795070060983
%N G.f.: g(x)^2 * g(x^2), where g(x) is the g.f. of A000081.
%H Vaclav Kotesovec, <a href="/A339985/b339985.txt">Table of n, a(n) for n = 0..2000</a>
%F a(n) ~ 2 * A339986 * A051491^n / n^(3/2).
%t 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]
%Y Cf. A000081, A217781, A339984.
%K nonn
%O 0,6
%A _Vaclav Kotesovec_, Dec 25 2020