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 A158197 #4 Feb 05 2015 14:13:42 %S A158197 1,4,23,140,866,5388,33603,209796,1310510,8188328,51169094,319779544, %T A158197 1998527188,12490460620,78064190235,487896926580,3049340393430, %U A158197 19058321475960,119114304522450,744463650984360,4652895041524380 %N A158197 Expansion of (1-x^2*c(x)^4)/(1-4*x*c(x)^2), c(x) the g.f. of A000108. %C A158197 Apply the inverse of the Riordan array (1/(1-x^2),x/(1+x)^2) to 4^n. Hankel transform is A070997. %F A158197 Conjecture: +4*(n+1)*a(n) +(-81*n+23)*a(n-1) +10*(51*n-70)*a(n-2) +500*(-2*n+5)*a(n-3)=0. - _R. J. Mathar_, Feb 05 2015 %F A158197 Conjecture: +4*(n+1)^2*a(n) +(-41*n^2-58*n+23)*a(n-1) +50*(n+2)*(2*n-3)*a(n-2)=0. - _R. J. Mathar_, Feb 05 2015 %Y A158197 Cf. A090317, A158196. %K A158197 easy,nonn %O A158197 0,2 %A A158197 _Paul Barry_, Mar 13 2009