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%I #6 Apr 13 2019 08:09:34
%S 1,4,24,144,828,4624,25296,136192,723160,3792564,19672240,101054512,
%T 514643952,2600665872,13049557280,65057605120,322413671228,
%U 1589046496704,7791836790504,38025622117168,184749163375664,893881787650016,4308024769339344,20685919693884672
%N Expansion of 1/theta_4(1/theta_4(x) - 1), where theta_4() is the Jacobi theta function.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/JacobiThetaFunctions.html">Jacobi Theta Functions</a>
%F G.f.: g(g(x) - 1), where g(x) = g.f. of A015128.
%t nmax = 23; CoefficientList[Series[1/EllipticTheta[4, 0, 1/EllipticTheta[4, 0, x] - 1], {x, 0, nmax}], x]
%t g[x_] := g[x] = Product[(1 + x^k)/(1 - x^k), {k, 1, 23}]; a[n_] := a[n] = SeriesCoefficient[g[g[x] - 1], {x, 0, n}]; Table[a[n], {n, 0, 23}]
%Y Cf. A002448, A015128, A307050, A307127, A307128, A307186.
%K nonn
%O 0,2
%A _Ilya Gutkovskiy_, Apr 12 2019