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 A207635 #5 Mar 30 2012 18:58:13 %S A207635 1,2,5,2,11,9,2,23,29,13,2,47,81,55,17,2,95,209,191,89,21,2,191,513, %T A207635 591,369,131,25,2,383,1217,1695,1329,631,181,29,2,767,2817,4607,4353, %U A207635 2591,993,239,33,2,1535,6401,12031,13313,9535,4577,1471,305,37,2 %N A207635 Triangle of coefficients of polynomials u(n,x) jointly generated with A207636; see the Formula section. %F A207635 u(n,x)=u(n-1,x)+v(n-1,x), %F A207635 v(n,x)=(x+1)*u(n-1,x)+(x+1)*v(n-1,x)+1, %F A207635 where u(1,x)=1, v(1,x)=1. %e A207635 First five rows: %e A207635 1 %e A207635 2 %e A207635 5....2 %e A207635 11...9....2 %e A207635 23...29...13...2 %t A207635 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A207635 u[n_, x_] := u[n - 1, x] + v[n - 1, x] %t A207635 v[n_, x_] := (x + 1)*u[n - 1, x] %t A207635 + (x + 1)*v[n - 1, x] + 1 %t A207635 Table[Factor[u[n, x]], {n, 1, z}] %t A207635 Table[Factor[v[n, x]], {n, 1, z}] %t A207635 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A207635 TableForm[cu] %t A207635 Flatten[%] (* A207635 *) %t A207635 Table[Expand[v[n, x]], {n, 1, z}] %t A207635 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A207635 TableForm[cv] %t A207635 Flatten[%] (* A207636 *) %Y A207635 Cf. A207636. %K A207635 nonn,tabf %O A207635 1,2 %A A207635 _Clark Kimberling_, Feb 24 2012