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 A167431 #5 Nov 13 2013 06:01:13 %S A167431 1,-4,1,4,-6,1,0,12,-8,1,0,-8,24,-10,1,0,0,-32,40,-12,1,0,0,16,-80,60, %T A167431 -14,1,0,0,0,80,-160,84,-16,1,0,0,0,-32,240,-280,112,-18,1,0,0,0,0, %U A167431 -192,560,-448,144,-20,1,0,0,0,0,64,-672,1120,-672,180,-22,1 %N A167431 Riordan array (1-4x+4x^2, x(1-2x)). %C A167431 Row sums are A167433. Diagonal sums are A167434. Central coefficients are (-1)^n*A001788(n+1). %C A167431 Inverse is A167432. %F A167431 T(n,k)=T(n-1,k-1)-2*T(n-2,k-1), T(0,0)=1, T(1,0)=-4, T(2,0)=4, T(n,k)=0 if k<0 or if k>n. - _Philippe Deléham_, Nov 13 2013 %e A167431 Triangle begins %e A167431 1, %e A167431 -4, 1, %e A167431 4, -6, 1, %e A167431 0, 12, -8, 1, %e A167431 0, -8, 24, -10, 1, %e A167431 0, 0, -32, 40, -12, 1, %e A167431 0, 0, 16, -80, 60, -14, 1, %e A167431 0, 0, 0, 80, -160, 84, -16, 1, %e A167431 0, 0, 0, -32, 240, -280, 112, -18, 1, %e A167431 0, 0, 0, 0, -192, 560, -448, 144, -20, 1, %e A167431 0, 0, 0, 0, 64, -672, 1120, -672, 180, -22, 1 %K A167431 easy,sign,tabl %O A167431 0,2 %A A167431 _Paul Barry_, Nov 03 2009