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 A208611 #5 Mar 30 2012 18:58:13 %S A208611 1,2,3,2,6,7,2,8,18,17,2,10,30,52,41,2,12,44,102,146,99,2,14,60,170, %T A208611 328,402,239,2,16,78,258,610,1014,1090,577,2,18,98,368,1016,2076,3044, %U A208611 2920,1393,2,20,120,502,1572,3756,6792,8932,7746,3363,2,22,144 %N A208611 Triangle of coefficients of polynomials v(n,x) jointly generated with A208610; see the Formula section. %F A208611 u(n,x)=u(n-1,x)+x*v(n-1,x), %F A208611 v(n,x)=(x+1)*u(n-1,x)+2x*v(n-1,x)+1, %F A208611 where u(1,x)=1, v(1,x)=1. %e A208611 First five rows: %e A208611 1 %e A208611 2...3 %e A208611 2...6....7 %e A208611 2...8....18...17 %e A208611 2...10...30...52...41 %e A208611 First five polynomials v(n,x): %e A208611 1 %e A208611 2 + 3x %e A208611 2 + 6x + 7x^2 %e A208611 2 + 8x + 18x^2 + 17x^3 %e A208611 2 + 10x + 30x^2 + 52x^3 + 41x^4 %t A208611 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A208611 u[n_, x_] := u[n - 1, x] + x*v[n - 1, x]; %t A208611 v[n_, x_] := (x + 1)*u[n - 1, x] + 2 x*v[n - 1, x] + 1; %t A208611 Table[Expand[u[n, x]], {n, 1, z/2}] %t A208611 Table[Expand[v[n, x]], {n, 1, z/2}] %t A208611 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A208611 TableForm[cu] %t A208611 Flatten[%] (* A208610 *) %t A208611 Table[Expand[v[n, x]], {n, 1, z}] %t A208611 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A208611 TableForm[cv] %t A208611 Flatten[%] (* A208611 *) %Y A208611 Cf. A208610. %K A208611 nonn,tabl %O A208611 1,2 %A A208611 _Clark Kimberling_, Mar 01 2012