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 A113145 #11 Sep 08 2013 13:30:50 %S A113145 1,1,2,8,60,708,11428,232756,5704964,163192820,5331728964, %T A113145 195776203764,7978838333188,357313060904692,17438518614448580, %U A113145 921145685670017012,52355425184381107332,3185815887918686343924,206633438251087758833476 %N A113145 Row 4 of table A113143; equal to INVERT of quartic (or 4-fold) factorials shifted one place right. %F A113145 a(n) = Sum_{j=0..k} 4^(k-j)*A111146(k, j). %F A113145 a(0) = 1; a(n+1) = Sum_{k=0..n} a(k)*A007696(n-k). %F A113145 G.f.: 1/(T(0) - x) where T(k) = 1 - x*(4*k+1)/(1 - x*(4*k+4)/T(k+1) ); (continued fraction). - _Sergei N. Gladkovskii_, Mar 19 2013 %e A113145 A(x) = 1 + x + 2*x^2 + 8*x^3 + 60*x^4 + 708*x^5 +... %e A113145 = 1/(1 - x - x^2 - 5*x^3 - 45*x^4 -...- A007696(n)*x^(n+1) %e A113145 -...). %o A113145 (PARI) {a(n)=local(x=X+X*O(X^n)); A=1/(1-x-x^2*sum(j=0,n,x^j*prod(i=0,j,4*i+1)));return(polcoeff(A,n,X))} %Y A113145 Cf. A113143, A007696 (4-fold factorials). %K A113145 nonn %O A113145 0,3 %A A113145 _Philippe Deléham_ and _Paul D. Hanna_, Oct 28 2005