cp's OEIS Frontend

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.

A111828 Matrix log of triangle A111825, which shifts columns left and up under matrix 6th power; these terms are the result of multiplying each element in row n and column k by (n-k)!.

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%I A111828 #10 Jun 13 2017 22:36:49
%S A111828 0,1,0,-4,6,0,42,-24,36,0,7296,252,-144,216,0,-7931976,43776,1512,
%T A111828 -864,1296,0,-45557382240,-47591856,262656,9072,-5184,7776,0,
%U A111828 3064554175021200,-273344293440,-285551136,1575936,54432,-31104,46656,0,801993619807364206080
%N A111828 Matrix log of triangle A111825, which shifts columns left and up under matrix 6th power; these terms are the result of multiplying each element in row n and column k by (n-k)!.
%C A111828 Column k equals 6^k multiplied by column 0 (A111829) when ignoring zeros above the diagonal.
%F A111828 T(n, k) = 6^k*T(n-k, 0) = A111829(n-k) for n>=k>=0.
%e A111828 Matrix log of A111825, with factorial denominators, begins:
%e A111828 0;
%e A111828 1/1!, 0;
%e A111828 -4/2!, 6/1!, 0;
%e A111828 42/3!, -24/2!, 36/1!, 0;
%e A111828 7296/4!, 252/3!, -144/2!, 216/1!, 0;
%e A111828 -7931976/5!, 43776/4!, 1512/3!, -864/2!, 1296/1!, 0; ...
%o A111828 (PARI) T(n,k,q=6)=local(A=Mat(1),B);if(n<k || k<0,0, for(m=1,n+1,B=matrix(m,m);for(i=1,m, for(j=1,i, if(j==i || j==1,B[i,j]=1,B[i,j]=(A^q)[i-1,j-1]);));A=B); B=sum(i=1,#A,-(A^0-A)^i/i);return((n-k)!*B[n+1,k+1]))
%Y A111828 Cf. A111825, A111829 (column 0); log matrices: A110504 (q=-1), A111813 (q=2), A111815 (q=3), A111818 (q=4), A111823 (q=5), A111833 (q=7), A111838 (q=8).
%K A111828 frac,sign,tabl
%O A111828 0,4
%A A111828 _Gottfried Helms_ and _Paul D. Hanna_, Aug 22 2005