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 A279216 Expansion of Product_{k>=1} 1/(1 - x^k)^(k^2*(k+1)/2). 10
 1, 1, 7, 25, 86, 269, 862, 2606, 7812, 22704, 64989, 182356, 504414, 1373694, 3693367, 9804435, 25733084, 66808578, 171719539, 437183839, 1103143657, 2760037810, 6850400668, 16873338215, 41260373472, 100196920196, 241712863504, 579416535973, 1380517695672, 3270075208145, 7702580246941 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Euler transform of the pentagonal pyramidal numbers (A002411). LINKS Vaclav Kotesovec, Table of n, a(n) for n = 0..1000 M. Bernstein and N. J. A. Sloane, Some canonical sequences of integers, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to arXiv version] M. Bernstein and N. J. A. Sloane, Some canonical sequences of integers, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210. [Link to Lin. Alg. Applic. version together with omitted figures] N. J. A. Sloane, Transforms Eric Weisstein's World of Mathematics, Pentagonal Pyramidal Number FORMULA G.f.: Product_{k>=1} 1/(1 - x^k)^(k^2*(k+1)/2). a(n) ~ exp(-Zeta(3)/(8*Pi^2) - Pi^16/(83980800000*Zeta(5)^3) + Zeta'(-3)/2 + (Pi^12/(97200000*2^(2/5)*3^(1/5)*Zeta(5)^(11/5))) * n^(1/5) + (-Pi^8/(108000*2^(4/5)*3^(2/5)*Zeta(5)^(7/5))) * n^(2/5) + (Pi^4/(180*2^(1/5)*(3*Zeta(5))^(3/5))) * n^(3/5) + ((5*(3*Zeta(5))^(1/5))/(2^(8/5))) * n^(4/5)) * (3*Zeta(5))^(119/1200) / (2^(181/600) * sqrt(5*Pi) * n^(719/1200)). - Vaclav Kotesovec, Dec 08 2016 MATHEMATICA nmax=30; CoefficientList[Series[Product[1/(1 - x^k)^(k^2 (k + 1)/2), {k, 1, nmax}], {x, 0, nmax}], x] CROSSREFS Cf. A000335, A002411, A279215, A279217, A279218, A279219. Sequence in context: A155294 A155233 A183914 * A245769 A146933 A155258 Adjacent sequences: A279213 A279214 A279215 * A279217 A279218 A279219 KEYWORD nonn AUTHOR Ilya Gutkovskiy, Dec 08 2016 STATUS approved

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Last modified December 1 08:20 EST 2022. Contains 358458 sequences. (Running on oeis4.)