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.

A102409 Even triangle n!. This table read by rows gives the coefficients of sum formulas of n-th factorials (A000142). The k-th row (6>=k>=1) contains T(i,k) for i=1 to k+3, where k=[2*n+1+(-1)^(n-1)]/4 and T(i,k) satisfies n! = Sum_{i=1..k+3} T(i,k) * n^(i-1) / (2*k-2)!.

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%I A102409 #16 Jun 16 2016 23:27:26
%S A102409 0,1,0,0,0,-20,8,0,0,20280,-6530,-1275,362,3,0,-8749440,21627600,
%T A102409 -4871940,-66510,48300,390,0,-261763004160,72965762016,13117344800,
%U A102409 -3757930680,72406040,13101144,90440,0,-974260634054400,-1140185248443360,353509119454680,-8136128999880,-3234018579750
%N A102409 Even triangle n!. This table read by rows gives the coefficients of sum formulas of n-th factorials (A000142). The k-th row (6>=k>=1) contains T(i,k) for i=1 to k+3, where k=[2*n+1+(-1)^(n-1)]/4 and T(i,k) satisfies n! = Sum_{i=1..k+3} T(i,k) * n^(i-1) / (2*k-2)!.
%C A102409 Incidentally, the sum of signed coefficients for each k-th row is divisible by (2*k-2)!. Moreover, another variant (but an incomplete one, and sorted differently) of the above sequence is presented in A101751.
%e A102409 Triangle starts:
%e A102409 0, 1, 0, 0;
%e A102409 0, -20, 8, 0, 0;
%e A102409 20280, -6530, -1275, 362, 3, 0;
%e A102409 -8749440, 21627600, -4871940, -66510, 48300, 390, 0;
%e A102409 -261763004160, 72965762016, 13117344800, -3757930680, 72406040, 13101144, 90440, 0;
%e A102409 ...
%e A102409 11!=39916800; substituting n=11 in the formula of the k-th row we obtain k=6 and the coefficients T(i,6) are those needed for computing 11!.
%e A102409 => 11! = [ -974260634054400 -1140185248443360*11 +353509119454680*11^2 -8136128999880*11^3 -3234018579750*11^4 +109743298560*11^5 +6053880420*11^6 +34067880*11^7 +9450*11^8 ]/10! = 39916800.
%Y A102409 Cf. A102410, A008276, A094216, A000142, A094638, A101751, A102411, A102412, A101752, A003422, A101559, A101032, A099731.
%K A102409 sign,tabf,uned
%O A102409 1,6
%A A102409 _André F. Labossière_, Jan 07 2005