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 A193847 #5 Mar 30 2012 18:57:38 %S A193847 2,8,4,26,28,8,80,136,80,16,242,568,512,208,32,728,2188,2672,1648,512, %T A193847 64,2186,8020,12392,10288,4832,1216,128,6560,28432,53216,55648,35072, %U A193847 13312,2816,256,19682,98416,216512,273376,216512,110080,35072 %N A193847 Mirror of the triangle A193846. %C A193847 A193847 is obtained by reversing the rows of the triangle A193846. %F A193847 Write w(n,k) for the triangle at A193846. The triangle at A193847 is then given by w(n,n-k). %e A193847 First six rows: %e A193847 2 %e A193847 8.....4 %e A193847 26....28....8 %e A193847 80....136...80....16 %e A193847 242...568...512...208...32 %e A193847 728...2188..2672..1648..512..64 %t A193847 p[n_, x_] := (x + 2)^n; %t A193847 q[n_, x_] := (x + 1)^n %t A193847 p1[n_, k_] := Coefficient[p[n, x], x^k]; %t A193847 p1[n_, 0] := p[n, x] /. x -> 0; %t A193847 d[n_, x_] := Sum[p1[n, k]*q[n - 1 - k, x], {k, 0, n - 1}] %t A193847 h[n_] := CoefficientList[d[n, x], {x}] %t A193847 TableForm[Table[Reverse[h[n]], {n, 0, z}]] %t A193847 Flatten[Table[Reverse[h[n]], {n, -1, z}]] (* A193846 *) %t A193847 TableForm[Table[h[n], {n, 0, z}]] %t A193847 Flatten[Table[h[n], {n, -1, z}]] (* A193847 *) %t A193847 TableForm[Table[Reverse[h[n]/2], {n, 0, z}]] %t A193847 Flatten[Table[Reverse[h[n]]/2, {n, -1, z}]] (* A193848 *) %t A193847 TableForm[Table[h[n]/2, {n, 0, z}]] %t A193847 Flatten[Table[h[n]/2, {n, -1, z}]] (* A193849 *) %Y A193847 Cf. A193846, A193849. %K A193847 nonn,tabl %O A193847 0,1 %A A193847 _Clark Kimberling_, Aug 07 2011