A120283 - OEIS

%I #2 Mar 31 2012 13:20:27

%S 5,1,-5,7,-15,7601,-91,3617,-745739,3317609,-5981591,5436374093,

%T -213827575,213745149261,-249859397004145,238988952277727,

%U -28354566442037,26315271553053477373,-108409774812137683,3394075340453838586663

%N Numerator of the coefficients of the k^2 terms of Sum[Sum[(i+j)^(2n),{i,1,k}],{j,1,k}].

%F a(n) = numerator[Coefficient[Sum[Sum[(i+j)^(2n),{i,1,k}],{j,1,k}],k,2]]. a(n) = A100615(2n) - bisection of the numerators of B(n)(2).

%t Numerator[Coefficient[Table[Sum[Sum[(i+j)^(2n),{i,1,k}],{j,1,k}],{n,1,20}],k,2]]

%Y Cf. A100615, A027643.

%K frac,sign

%O 1,1

%A _Alexander Adamchuk_, Jul 06 2006