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 A158196 #4 Feb 05 2015 14:10:45 %S A158196 1,3,14,71,370,1950,10332,54895,292106,1555706,8289732,44186710, %T A158196 235575028,1256093084,6698073528,35719158591,190488112122, %U A158196 1015885525794,5417869631028,28894620083346,154102115782812 %N A158196 Expansion of (1-x^2*c(x)^4)/(1-3*x*c(x)^2), c(x) the g.f. of A000108. %C A158196 Apply the inverse of the Riordan array (1/(1-x^2),x/(1+x)^2) to 3^n. Hankel transform is A001653. %F A158196 Conjecture: +3*(n+1)*a(n) +2*(-26*n+7)*a(n-1) +16*(18*n-25)*a(n-2) +256*(-2*n+5)*a(n-3)=0. - _R. J. Mathar_, Feb 05 2015 %F A158196 Conjecture: 3*(2*n+3)*(n+1)*a(n) +2*(-28*n^2-52*n+21)*a(n-1) +32*(2*n+5)*(2*n-3)*a(n-2)=0. - _R. J. Mathar_, Feb 05 2015 %Y A158196 Cf. A090317. %K A158196 easy,nonn %O A158196 0,2 %A A158196 _Paul Barry_, Mar 13 2009