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A066395 Expansion of reciprocal of j-function (see A000521). 15
1, -744, 356652, -140361152, 49336682190, -16114625669088, 4999042477430456, -1492669384085015040, 432762759484818142437, -122566701136436206749360, 34058364214245581228710692, -9315629487329800685570383104, 2514284824201628853303708453062 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..421

FORMULA

a(n) ~ c * (-1)^(n+1) * exp(Pi*sqrt(3)*n) * n^2, where c = 0.00271122282373677410826992857036010754653235515106627... - Vaclav Kotesovec, Jun 28 2017

EXAMPLE

q*(1 - 744*q + 356652*q^2 - 140361152*q^3 + 49336682190*q^4 - 16114625669088*q^5 + ...).

MATHEMATICA

nmax = 20; Rest[CoefficientList[Series[(1 - (1 - 504*Sum[DivisorSigma[5, k]*x^k, {k, 1, nmax}])^2/(1 + 240*Sum[DivisorSigma[3, k]*x^k, {k, 1, nmax}])^3)/1728, {x, 0, nmax}], x]] (* Vaclav Kotesovec, Jul 07 2017 *)

CROSSREFS

Sequence in context: A000521 A178449 A178451 * A161557 A091406 A066396

Adjacent sequences:  A066392 A066393 A066394 * A066396 A066397 A066398

KEYWORD

sign

AUTHOR

N. J. A. Sloane, Dec 24 2001

STATUS

approved

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Last modified July 24 08:32 EDT 2017. Contains 289717 sequences.