%I #12 Feb 26 2018 10:18:39
%S 691,-631008,220745952,-97839374976,19569814631136,4535334591238080,
%T 303188772007707264,10484562664742729472,226123357637141848800,
%U 3395301924051385082784,38309171317486687195200,343029821520447762390144,2537867756328299498904192
%N Coefficients in expansion of 691*E_6^2*E_12.
%H Seiichi Manyama, <a href="/A290010/b290010.txt">Table of n, a(n) for n = 0..1000</a>
%t terms = 13;
%t E6[x_] = 1 - 504*Sum[k^5*x^k/(1 - x^k), {k, 1, terms}];
%t E12[x_] = 1 + (65520/691)*Sum[k^11*x^k/(1 - x^k), {k, 1, terms}];
%t 691*E6[x]^2*E12[x] + O[x]^terms // CoefficientList[#, x]& (* _Jean-François Alcover_, Feb 26 2018 *)
%Y Cf. A013973 (E_6), A029828 (691*E_12), A280869 (E_6^2).
%Y Cf. A290009.
%K sign
%O 0,1
%A _Seiichi Manyama_, Jul 17 2017