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 A280423 G.f.: Product_{k>=1} (1 + x^(k*(k+1))) / (1 - x^k). 1

%I

%S 1,1,3,4,7,10,17,23,36,49,71,96,136,180,248,326,437,569,752,967,1261,

%T 1609,2069,2620,3335,4189,5285,6595,8249,10230,12706,15661,19327,

%U 23696,29063,35457,43256,52519,63756,77073,93126,112120,134901,161781,193884,231679

%N G.f.: Product_{k>=1} (1 + x^(k*(k+1))) / (1 - x^k).

%F a(n) ~ exp(sqrt(2*n/3)*Pi + 3^(1/4) * (sqrt(2)-1) * Zeta(3/2) * n^(1/4) / 2^(5/4) + 3*(2*sqrt(2)-3) * Zeta(3/2)^2 / (64*Pi)) / (8*sqrt(3)*n).

%t nmax=60; CoefficientList[Series[Product[(1+x^(k*(k+1)))/(1-x^k), {k, 1, nmax}], {x, 0, nmax}], x]

%Y Cf. A024940, A000041, A280421.

%K nonn

%O 0,3

%A _Vaclav Kotesovec_, Jan 02 2017

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Last modified August 5 22:09 EDT 2020. Contains 336214 sequences. (Running on oeis4.)