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%I #25 Aug 11 2021 06:29:02
%S 1,-504,180252,-56364992,16415391870,-4574618335008,1237162549543256,
%T -327377686829760000,85212608926827807477,-21894492009015306942480,
%U 5567179862617316105012532,-1403483985988949037403977984
%N Expansion of Delta(tau)/E_4(tau)^2.
%C According to Paşol and Zudilin, a(n) is divisible by n. - _F. Chapoton_, Aug 10 2021
%H Seiichi Manyama, <a href="/A105097/b105097.txt">Table of n, a(n) for n = 1..423</a>
%H Richard E. Borcherds, <a href="https://arxiv.org/abs/alg-geom/9609022">Automorphic forms with singularities on Grassmannians</a>, arXiv:alg-geom/9609022, 1996-1997; Invent. Math. 132 (1998), 491-562.
%H Vicenţiu Paşol and Wadim Zudilin, <a href="https://arxiv.org/abs/2009.14609">Magnetic (quasi-)modular forms</a>, arXiv:2009.14609 [math.NT], 2020.
%F a(n) ~ -(-1)^n * exp(Pi*sqrt(3)*n) * n / 192. - _Vaclav Kotesovec_, Jun 07 2018
%o (PARI) {a(n)=if(n<1,0,polcoeff( x*eta(x+x*O(x^n))^24/sum(k=1,n,480*sigma(k,7)*x^k,1),n))} /* _Michael Somos_, Apr 07 2005 */
%Y Cf. A000594, A004009, A008410.
%K sign,easy
%O 1,2
%A _N. J. A. Sloane_, Apr 07 2005
%E More terms from _Michael Somos_, Apr 07 2005
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