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 A161801 #4 Mar 30 2012 18:37:17
%S A161801 1,-6,-8,112,-86,-752,1360,1216,-5384,10762,-8176,-59888,130160,47696,
%T A161801 -306336,485952,-632982,-1582304,4638088,343120,-6514672,8034464,
%U A161801 -16636656,-20670528,82724176,17877578,-114481936,52539968,-178638656
%N A161801 G.f. is Q_0(q) where Q_0(q^4) is a series quadrisection of the g.f. of A161800.
%C A161801 The g.f. of A161800 has two nonzero series quadrisections; the other is given by A161802.
%e A161801 G.f.: Q_0(q) = 1 - 6*q - 8*q^2 + 112*q^3 - 86*q^4 - 752*q^5 + 1360*q^6 +...
%o A161801 (PARI) {a(n)=local(L=sum(m=1, 4*n,2*2^valuation(m,2)*sumdiv(m, d, -(-1)^d*d)*x^m/m)+x*O(x^(4*n))); polcoeff(exp(L), 4*n)}
%Y A161801 Cf. A161800, A161802.
%K A161801 sign
%O A161801 0,2
%A A161801 _Paul D. Hanna_, Jul 19 2009