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 A202847 #18 Mar 05 2013 15:26:07
%S A202847 1,-1,1,2,-2,1,-3,5,-3,1,6,-10,9,-4,1,-10,22,-22,14,-5,1,20,-44,54,
%T A202847 -40,20,-6,1,-35,93,-123,109,-65,27,-7,1,70,-186,281,-276,195,-98,35,
%U A202847 -8,1,-126,386,-618,682,-541,321,-140,44,-9,1
%N A202847 Riordan array (f(x), x*f(x)) where f(x) is the g.f. of A126930.
%F A202847 T(n,k) = (-1)^(n-k)*A054336(n,k).
%F A202847 Sum_{k, 0<=k<=n}T(n,k)*x^k = (-1)^n*A126931(n), (-1)^n*A054341(n), A126930(n), A126120(n), A001405(n), A054341(n), A126931(n) for x = -2, -1, 0, 1, 2, 3, 4 respectively.
%e A202847 Triangle begins
%e A202847 1
%e A202847 -1, 1
%e A202847 2, -2, 1
%e A202847 -3, 5, -3, 1
%e A202847 6, -10, 9, -4, 1
%e A202847 -10, 22, -22, 14, -5, 1
%e A202847 20, -44, 54, -40, 20, -6, 1
%e A202847 -35, 93, -123, 109, -65, 27, -7, 1
%e A202847 ...
%e A202847 Production matrix begins
%e A202847 x, 1
%e A202847 1, x, 1
%e A202847 1, 1, x, 1
%e A202847 1, 1, 1, x, 1
%e A202847 1, 1, 1, 1, x, 1
%e A202847 1, 1, 1, 1, 1, x, 1
%e A202847 1, 1, 1, 1, 1, 1, x, 1
%e A202847 1, 1, 1, 1, 1, 1, 1, x, 1
%e A202847 1, 1, 1, 1, 1, 1, 1, 1, x, 1
%e A202847 1, 1, 1, 1, 1, 1, 1, 1, 1, x, 1
%e A202847 ..., with x = -1.
%Y A202847 Cf. (sequences with similar production matrix) A097609 (x=0), A033184 (x=1), A104259 (x=2), A171568 (x=3), A171589 (x=4)
%K A202847 sign,tabl
%O A202847 0,4
%A A202847 _Philippe Deléham_, Mar 02 2013