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 A246788 #14 Nov 21 2014 02:21:28 %S A246788 1,-3,2,9,-10,3,-23,38,-21,4,57,-122,99,-36,5,-135,358,-381,204,-55,6, %T A246788 313,-986,1299,-916,365,-78,7,-711,2598,-4077,3564,-1875,594,-105,8, %U A246788 1593,-6618,12051,-12564,8205,-3438,903,-136,9,-3527,16422,-34029,41196,-32115,16722,-5817,1304,-171,10 %N A246788 Triangle read by rows: T(n,k) is the coefficient A_k in the transformation Sum_{k=0..n} (k+1)*x^k = Sum_{k=0..n} A_k*(x+2)^k. %C A246788 Consider the transformation 1 + 2x + 3x^2 + 4x^3 + ... + (n+1)*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 A246788 T(n,0) = ((6*n+8)*(-2)^n+1)/9, for n >= 0. %F A246788 T(n,n-1) = -n*(2*n+1), for n >= 1. %F A246788 Row n sums to A001057(n+1). %e A246788 1; %e A246788 -3, 2; %e A246788 9, -10, 3; %e A246788 -23, 38, -21, 4; %e A246788 57, -122, 99, -36, 5; %e A246788 -135, 358, -381, 204, -55, 6; %e A246788 313, -986, 1299, -916, 365, -78, 7; %e A246788 -711, 2598, -4077, 3564, -1875, 594, -105, 8; %e A246788 1593, -6618, 12051, -12564, 8205, -3438, 903, -136, 9; %e A246788 -3527, 16422, -34029, 41196, -32115, 16722, -5817, 1304, -171, 10; %o A246788 (PARI) T(n,k) = (k+1)*sum(i=0,n-k,(-2)^i*binomial(i+k+1,k+1)) %o A246788 for(n=0,10,for(k=0,n,print1(T(n,k),", "))) %Y A246788 Cf. A248345, A045883, A014105, A001057. %K A246788 sign,tabl %O A246788 0,2 %A A246788 _Derek Orr_, Nov 15 2014