A282017 - OEIS

%I #12 Feb 05 2017 01:36:45

%S 1,96,1296,4992,13488,25920,50112,74496,123120,164832,246240,300672,

%T 442176,501312,694656,794880,1052016,1135296,1534032,1591680,2086560,

%U 2214912,2763072,2840832,3723840,3668640,4590432,4750080,5801088,5728320,7309440,7007232,8697456,8722944,10349856,10160640

%N Coefficients in q-expansion of (E_4 + E_2^2)/2, where E_2 and E_4 are the Eisenstein series shown in A006352 and A004009, respectively.

%p with(numtheory); M:=100;

%p E := proc(k) local n, t1; global M;

%p t1 := 1-(2*k/bernoulli(k))*add(sigma[k-1](n)*q^n, n=1..M+1);

%p series(t1, q, M+1); end;

%p e2:=E(2); e4:=E(4); e6:=E(6);

%p series((e2^2+e4)/2,q,M+1);

%p seriestolist(%);

%Y Cf. A004009 and A006352.

%K nonn

%O 0,2

%A _N. J. A. Sloane_, Feb 05 2017