A265821 - OEIS

A265821

Expansion of Product_{k>=1} 1/(1 - (3*k-2)*x^(3*k-2)).

1, 1, 1, 1, 5, 5, 5, 12, 28, 28, 38, 66, 130, 143, 232, 344, 616, 738, 1094, 1561, 2840, 3671, 5117, 7227, 12833, 16182, 22428, 32205, 57058, 71006, 98684, 141253, 241563, 301889, 421994, 610113, 1018507, 1278706, 1784671, 2549610, 4224964, 5333003, 7491698

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OFFSET

0,5

LINKS

Vaclav Kotesovec, Table of n, a(n) for n = 0..5000

FORMULA

a(n) ~ c * 2^(n/2), where

c = 4.633065657780064798394952757560310709647495826095820632429... if mod(n,4) = 0

c = 4.169885941972377533366541853673119715620037601993736640548... if mod(n,4) = 1

c = 4.088913297791237602600754017373520586356446410096065167531... if mod(n,4) = 2

c = 4.069986547973463713613958049535085419215417774875202440925... if mod(n,4) = 3.

MATHEMATICA

nmax = 40; CoefficientList[Series[Product[1/(1 - (3*k-2)*x^(3*k-2)), {k, 1, nmax}], {x, 0, nmax}], x]

CROSSREFS

Cf. A067553, A265820.

Sequence in context: A101597 A119991 A262947 * A266953 A224165 A330318

Adjacent sequences: A265818 A265819 A265820 * A265822 A265823 A265824

KEYWORD

nonn

AUTHOR

Vaclav Kotesovec, Dec 15 2015

STATUS

approved