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%I #15 Oct 30 2016 18:48:23
%S 2,1,4,4,13,14,36,48,96,141,261,386,676,1030,1706,2619,4230,6462,
%T 10219,15568,24165,36627,56103,84428,127873,191201,286663,425802,
%U 632973,933995,1377774,2020424,2959438,4314109,6278824,9100908,13167388,18983295,27313916,39177636,56080228,80048942,114030110,162018938,229741517,325000341,458854803,646409612
%N Second differences of A000219.
%D G. Almkvist, The differences of the number of plane partitions, Manuscript, circa 1991.
%F a(n) ~ 2^(13/36) * Zeta(3)^(31/36) * exp(1/12 + 3*Zeta(3)^(1/3)*n^(2/3)/2^(2/3)) / (A * sqrt(3*Pi) * n^(49/36)), where Zeta(3) = A002117 and A = A074962 is the Glaisher-Kinkelin constant. - _Vaclav Kotesovec_, Oct 30 2016
%t Differences[CoefficientList[Series[Product[(1-x^k)^-k, {k,1,64}], {x,0,64}],x],2] (* _Harvey P. Dale_, Jun 19 2011 *)
%t nmax = 50; Drop[CoefficientList[Series[(1-x)^2 * Product[1/(1-x^k)^k, {k, 1, nmax}], {x, 0, nmax}], x], 2] (* _Vaclav Kotesovec_, Oct 30 2016 *)
%Y Cf. A000219, A191659, A191661.
%K nonn
%O 0,1
%A _N. J. A. Sloane_, Jun 10 2011
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