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Coefficients in q-expansion of E_2*E_4^2, where E_2, E_4 are the Eisenstein series shown in A006352, A004009, respectively.
11

%I #14 Feb 23 2018 03:40:41

%S 1,456,50328,-470496,-21784008,-234371664,-1446514848,-6502690752,

%T -23328111240,-71276388312,-191952331632,-468159788448,-1052750026272,

%U -2212261706256,-4394299104576,-8303419066176,-15060718806024,-26284654025712,-44471780630856

%N Coefficients in q-expansion of E_2*E_4^2, where E_2, E_4 are the Eisenstein series shown in A006352, A004009, respectively.

%H Seiichi Manyama, <a href="/A282101/b282101.txt">Table of n, a(n) for n = 0..1000</a>

%t terms = 19;

%t E2[x_] = 1 - 24*Sum[k*x^k/(1 - x^k), {k, 1, terms}];

%t E4[x_] = 1 + 240*Sum[k^3*x^k/(1 - x^k), {k, 1, terms}];

%t E2[x]*E4[x]^2 + O[x]^terms // CoefficientList[#, x]& (* _Jean-François Alcover_, Feb 23 2018 *)

%Y Cf. A006352 (E_2), A004009 (E_4), A008410 (E_8).

%Y Cf. A281374 (E_2^2), A282019 (E_2*E_4), A282096 (E_2*E_6), this sequence (E_2*E_8), A282102 (E_2*E_10).

%K sign

%O 0,2

%A _Seiichi Manyama_, Feb 06 2017