This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A119784 #2 Mar 31 2012 13:20:27
%S A119784 1,15,1519,23575,15907111,5224037,13034567237,206747823917,
%T A119784 51412399560631,10224262569323,152012226379719803,151406414338463843,
%U A119784 4372018721271579430163,4359099317599237566323,21975413631947472215359
%N A119784 Numerator of Sum[Sum[(-1)^(i+1)*1/(i*j)^2, {i, 1, n}], {j, 1, n}].
%C A119784 Prime p divides a((p-1)/2) for p>3. p^2 divides a(p-1) for prime p>3.
%F A119784 a(n) = numerator[Sum[Sum[(-1)^(i+1)*1/(i*j)^2, {i, 1, n}], {j, 1, n}]]. a(n) = A119682(n)*A007406(n).
%t A119784 Numerator[Table[Sum[Sum[(-1)^(i+1)*1/(i*j)^2, {i, 1, n}], {j, 1, n}],{n,1,20}]]
%Y A119784 Cf. A007406, A119682.
%K A119784 frac,nonn
%O A119784 1,2
%A A119784 _Alexander Adamchuk_, Jun 25 2006