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A035298
Expansion of sum ( q^n / product( 1-q^k, k=1..6*n), n=0..inf ).
4
1, 1, 2, 4, 7, 12, 19, 30, 44, 65, 93, 132, 183, 253, 343, 462, 616, 816, 1071, 1399, 1813, 2339, 2999, 3828, 4861, 6149, 7743, 9714, 12140, 15120, 18766, 23220, 28640, 35224, 43199, 52838, 64458, 78441, 95226, 115336, 139381, 168077, 202258, 242900, 291140, 348300, 415922
OFFSET
0,3
COMMENTS
In general, for m>=1, if g.f. = Sum_{k>=0} x^k / Product_{j=1..m*k} (1 - x^j), then a(n) ~ Gamma(1/m) * exp(Pi*sqrt(2*n/3)) / (m * 2^((3*m + 1)/(2*m)) * 3^(1/(2*m)) * Pi^(1 - 1/m) * n^((m+1)/(2*m))). - Vaclav Kotesovec, Jun 17 2025
LINKS
FORMULA
a(n) ~ Gamma(1/6) * exp(Pi*sqrt(2*n/3)) / (2^(31/12) * 3^(13/12) * Pi^(5/6) * n^(7/12)). - Vaclav Kotesovec, Jun 17 2025
MATHEMATICA
nmax = 50; CoefficientList[Series[Sum[x^k/Product[1 - x^j, {j, 1, 6*k}], {k, 0, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Jun 16 2025 *)
nmax = 50; p=1; s=1; Do[p=Expand[p*(1-x^(6*k))*(1-x^(6*k-1))*(1-x^(6*k-2))*(1-x^(6*k-3))*(1-x^(6*k-4))*(1-x^(6*k-5))]; p=Take[p, Min[nmax+1, Exponent[p, x]+1, Length[p]]]; s+=x^k/p; , {k, 1, nmax}]; CoefficientList[Series[s, {x, 0, nmax}], x] (* Vaclav Kotesovec, Jun 16 2025 *)
CROSSREFS
Sequence in context: A175965 A288341 A347542 * A288342 A347543 A343940
KEYWORD
nonn
EXTENSIONS
More terms from Vaclav Kotesovec, Jun 16 2025
STATUS
approved