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 A117160 #7 May 31 2013 18:56:02
%S A117160 1,1,2,4,9,19,43,94,210,464,1035,2295,5111,11352,25259,56145,124888,
%T A117160 277669,617554,1373201,3053883,6790995,15102178,33583784,74684504,
%U A117160 166082706,369337117,821331578,1826484804,4061741926,9032530513
%N A117160 Column 1 of triangle A112682; also equals row sums of A112682 (with offset).
%C A117160 G.f.: A(x) = g.f. of A117169 (Shift-Moebius[1,1,1,1,...]) divided by the g.f. of A117166 (Shift-Moebius[1,0,0,0,...]) (see A117165 for the Shift-Moebius transform coefficients).
%C A117160 Limit_{n->oo} a(n+1)/a(n) = 2.223805416529545241557...
%o A117160 (PARI) {a(n)=if(n<1,0,SM=prod(i=0,n,matrix(n,n,r,c,if(r>=c, if((r+n-i)%(c+n-i)==0,moebius((r+n-i)/(c+n-i)),0)))); U=SM*vector(n,i,1)~;V=SM*vector(n,i,if(i==1,1,0))~; return(Vec(Ser(U)/Ser(V))[n]))}
%Y A117160 Cf. A112682, A117165 (Shift-Moebius), A117169, A117166, A117161.
%K A117160 nonn
%O A117160 1,3
%A A117160 _Wouter Meeussen_ and _Paul D. Hanna_, Feb 28 2006