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 A384951 #22 Jun 14 2025 10:37:37 %S A384951 1,1,2,3,5,6,2,-20,-102,-312,-795,-1483,-1102,7035,51059,219453, %T A384951 779078,2307104,5508377,7633065,-19349069,-226127800,-1296826960, %U A384951 -5855601434,-22970901723,-78578482054,-224208769108,-429111559993,429212740026,10534398465308 %N A384951 G.f. A(x) satisfies A(x) = 1 + x*A(x)/A(-x*A(x)). %C A384951 Compare to: B(x) = 1 + x/B(-x*B(x)) holds when B(x) = 1/(1-x). %F A384951 See A384976. %o A384951 (PARI) a(n, k=-1) = if(n*k==0, 0^n, (-1)^n*k*sum(j=1, n, binomial(-n+j+k-1, j-1)*a(n-j, j)/j)); %Y A384951 Column k=1 of A384976. %K A384951 sign %O A384951 0,3 %A A384951 _Seiichi Manyama_, Jun 14 2025