A282018 Coefficients in q-expansion of E_2^3, where E_2 is the Eisenstein series shown in A006352.

1, -72, 1512, -3744, -95544, -473904, -1538784, -3947328, -8597880, -16987176, -30607632, -52030944, -83972448, -129500784, -194056128, -279446976, -397468152, -544155408, -743106744, -978896160, -1296984528, -1654458624, -2139055776, -2661349824, -3370243680, -4106376504, -5113466064

Offset

0,2

Links

Seiichi Manyama, Table of n, a(n) for n = 0..1000

Maple

with(numtheory); M:=100;
E := proc(k) local n, t1; global M;
t1 := 1-(2*k/bernoulli(k))*add(sigma[k-1](n)*q^n, n=1..M+1);
series(t1, q, M+1); end;
e2:=E(2); e4:=E(4); e6:=E(6);
series(e2^3, q, M+1);
seriestolist(%);

Mathematica

terms = 27;
E2[x_] = 1 - 24*Sum[k*x^k/(1 - x^k), {k, 1, terms}];
E2[x]^3 + O[x]^terms // CoefficientList[#, x]& (* Jean-François Alcover, Feb 23 2018 *)

Crossrefs

Cf. A006352.

Sequence in context: A367781 A008391 A292881 * A037251 A352994 A234209

Adjacent sequences: A282015 A282016 A282017 * A282019 A282020 A282021

Keyword

sign

Author

N. J. A. Sloane, Feb 05 2017

Status

approved