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 A145200 Coefficients of expansion of Phi(tau) = E_2*E_4/(E_6*j). 2
 0, 1, -24, 196812, 38262208, 40310333070, 16012430173152, 10091293275887096, 5000566664612497920, 2783095702986935913957, 1463183098457857467833520, 790439623931093138858233092, 421526637613212526260386954496, 226162012708702132169932739559302, 120998755205524059896241960291393216 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Seiichi Manyama, Table of n, a(n) for n = 0..367 M. Kaneko and D. Zagier, Supersingular j-invariants, hypergeometric series and Atkin's orthogonal polynomials, pp. 97-126 of D. A. Buell and J. T. Teitelbaum, eds., Computational Perspectives on Number Theory, Amer. Math. Soc., 1998 Eric Weisstein's World of Mathematics, Eisenstein Series. FORMULA a(n) ~ 2 * Pi^5 * exp(2*Pi*n) / (27 * Gamma(1/4)^8). - Vaclav Kotesovec, Apr 07 2018 EXAMPLE G.f. = q - 24*q^2 + 196812*q^3 + 38262208*q^4 + 40310333070*q^5 + 16012430173152*q^6 + ... MATHEMATICA a[ n_] := SeriesCoefficient[ (1 - 24 Sum[ DivisorSigma[ 1, k] x^k, {k, n}]) (1 + 240 Sum[ DivisorSigma[ 3, k] x^k, {k, n}]) / ((1 - 504 Sum[ DivisorSigma[ 5, k] x^k, {k, n}]) KleinInvariantJ[ Log[x] / (2 Pi I)] 1728), {x, 0, n}]; (* Michael Somos, Jan 15 2015 *) CROSSREFS Cf. A000521 (j), A006352 (E_2), A004009 (E_4), A013973 (E_6), A030185. Sequence in context: A048057 A305757 A058550 * A007240 A289029 A287964 Adjacent sequences:  A145197 A145198 A145199 * A145201 A145202 A145203 KEYWORD sign AUTHOR N. J. A. Sloane, Feb 28 2009 STATUS approved

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Last modified October 14 07:19 EDT 2019. Contains 327995 sequences. (Running on oeis4.)