A378468 Coefficients in expansion of (1/E_4)^3.
1, -720, 339120, -132039360, 46081214640, -14974899930720, 4627836408778560, -1377759164154871680, 398508058352289409200, -112648427646194257313040, 31252327416307233967209120, -8536592939398421710286859840, 2301363255613811638678456000320, -613491781086725734777586106900960
Offset: 0
Keywords
Programs
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Mathematica
nmax = 20; CoefficientList[Series[(1+240*Sum[DivisorSigma[3, k]*x^k, {k, 1, nmax}])^(-3), {x, 0, nmax}], x]
Formula
a(n) ~ (-1)^n * 67108864 * Pi^36 * n^2 * exp(Pi*sqrt(3)*n) / (729 * Gamma(1/3)^54).