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 A111829 #7 Mar 13 2015 00:06:35 %S A111829 0,1,-4,42,7296,-7931976,-45557382240,3064554175021200, %T A111829 801993619807364206080,-2618439032548254776387771520, %U A111829 -30580166025709706974876961026475520,4440597519115996836838709580481861376121600 %N A111829 Column 0 of the matrix logarithm (A111828) of triangle A111825, which shifts columns left and up under matrix 6th power; these terms are the result of multiplying the element in row n by n!. %C A111829 Let q=6; the g.f. of column k of A111825^m (matrix power m) is: 1 + Sum_{n>=1} (m*q^k)^n/n! * Product_{j=0..n-1} A(q^j*x). %F A111829 E.g.f. satisfies: x/(1-x) = Sum_{n>=1} Prod_{j=0..n-1} A(6^j*x)/(j+1). %e A111829 A(x) = x - 4/2!*x^2 + 42/3!*x^3 + 7296/4!*x^4 - 7931976/5!*x^5 +... %e A111829 where e.g.f. A(x) satisfies: %e A111829 x/(1-x) = A(x) + A(x)*A(6*x)/2! + A(x)*A(6*x)*A(6^2*x)/3! + %e A111829 A(x)*A(6*x)*A(6^2*x)*A(6^3*x)/4! + ... %e A111829 Let G(x) be the g.f. of A111826 (column 1 of A111825), then %e A111829 G(x) = 1 + 6*A(x) + 6^2*A(x)*A(6*x)/2! + %e A111829 6^3*A(x)*A(6*x)*A(6^2*x)/3! + %e A111829 6^4*A(x)*A(6*x)*A(6^2*x)*A(6^3*x)/4! + ... %o A111829 (PARI) {a(n,q=6)=local(A=x/(1-x+x*O(x^n)));for(i=1,n, A=x/(1-x)/(1+sum(j=1,n,prod(k=1,j,subst(A,x,q^k*x))/(j+1)!))); return(n!*polcoeff(A,n))} %Y A111829 Cf. A111825 (triangle), A111826, A111828 (matrix log); A110505 (q=-1), A111814 (q=2), A111816 (q=3), A111819 (q=4), A111824 (q=5), A111834 (q=7), A111839 (q=8). %K A111829 sign %O A111829 0,3 %A A111829 _Gottfried Helms_ and _Paul D. Hanna_, Aug 22 2005