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.

A102411 Even triangle !n. This table read by rows gives the coefficients of sum formulas of n-th Left factorials (A003422). The k-th row (6>=k>=1) contains T(i,k) for i=1 to k+2, where k=[2*n+1+(-1)^(n-1)]/4 and T(i,k) satisfies !n = Sum_{i=1..k+2} T(i,k) * n^(i-1) / (2*k-2)!.

This page as a plain text file.
%I A102411 #19 Jun 16 2016 23:27:27
%S A102411 0,1,0,-16,5,1,0,5256,-3068,276,32,0,2070720,2367420,-912150,53220,
%T A102411 3510,0,-36031524480,15327895296,-40587120,-387492840,21414120,758184,
%U A102411 840,-212459319878400,-75473246681280,38182549456800,-2562251680800,-195611371200,13639812480,285616800,453600
%N A102411 Even triangle !n. This table read by rows gives the coefficients of sum formulas of n-th Left factorials (A003422). The k-th row (6>=k>=1) contains T(i,k) for i=1 to k+2, where k=[2*n+1+(-1)^(n-1)]/4 and T(i,k) satisfies !n = Sum_{i=1..k+2} T(i,k) * n^(i-1) / (2*k-2)!.
%C A102411 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 A101752.
%e A102411 Triangle starts:
%e A102411 0, 1, 0;
%e A102411 -16, 5, 1, 0;
%e A102411 5256, -3068, 276, 32, 0;
%e A102411 2070720, 2367420, -912150, 53220, 3510, 0;
%e A102411 -36031524480, 15327895296, -40587120, -387492840, 21414120, 758184, 840;
%e A102411 ...
%e A102411 !11=4037914; 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 A102411 => !11 = [ -212459319878400 -75473246681280*11 +38182549456800*11^2 -2562251680800*11^3 -195611371200*11^4 +13639812480*11^5 +285616800*11^6 +453600*11^7 ]/10! = 4037914.
%Y A102411 Cf. A102412, A094638, A094216, A003422, A008276, A101752, A102409, A102410, A101751, A000142, A101559, A101032, A099731.
%K A102411 sign,tabf,uned
%O A102411 1,4
%A A102411 _André F. Labossière_, Jan 07 2005