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 A248810 #14 Oct 17 2014 23:54:25 %S A248810 1,-1,1,3,-3,1,-5,9,-5,1,11,-23,19,-7,1,-21,57,-61,33,-9,1,43,-135, %T A248810 179,-127,51,-11,1,-85,313,-493,433,-229,73,-13,1,171,-711,1299,-1359, %U A248810 891,-375,99,-15,1,-341,1593,-3309,4017,-3141,1641,-573,129,-17,1,683,-3527,8211,-11343,10299,-6423,2787,-831,163,-19,1 %N A248810 Signed version of A164984. %C A248810 Consider the transformation 1 + x + x^2 + x^3 + ... + x^n = A_0*(x+2)^0 + A_1*(x+2)^1 + A_2*(x+2)^2 + ... + A_n*(x+2)^n. This sequence gives A_0, ... A_n as the entries in the n-th row of this triangle, starting at n = 0. %F A248810 T(n,n-1) = -2*n+1 for n > 0. %F A248810 T(n,n-2) = 2*(n-1)^2+1 for n > 1. %F A248810 T(n,0) = A077925(n). %F A248810 T(n,1) = (-1)^(n+1)*A045883(n). %F A248810 Rows with odd n sum to 0. %F A248810 Rows with even n sum to 1. %e A248810 1; %e A248810 -1, 1; %e A248810 3, -3, 1; %e A248810 -5, 9, -5, 1; %e A248810 11, -23, 19, -7, 1; %e A248810 -21, 57, -61, 33, -9, 1; %e A248810 43, -135, 179, -127, 51, -11, 1; %e A248810 -85, 313, -493, 433, -229, 73, -13, 1; %e A248810 171, -711, 1299, -1359, 891, -375, 99, -15, 1; %e A248810 -341, 1593, -3309, 4017, -3141, 1641, -573, 129, -17, 1; %e A248810 683, -3527, 8211, -11343, 10299, -6423, 2787, -831, 163, -19, 1; %o A248810 (PARI) for(n=0,20,for(k=0,n,print1(1/k!*sum(i=0,n,((-2)^(i-k)*prod(j=0,k-1,i-j))),", "))) %Y A248810 Cf. A164984, A193845, A077925, A045883. %K A248810 sign,tabl %O A248810 0,4 %A A248810 _Derek Orr_, Oct 14 2014