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 A208610 #5 Mar 30 2012 18:58:13 %S A208610 1,1,1,1,3,3,1,5,9,7,1,7,17,25,17,1,9,27,55,69,41,1,11,39,99,171,187, %T A208610 99,1,13,53,159,341,515,501,239,1,15,69,237,599,1125,1515,1329,577,1, %U A208610 17,87,335,967,2141,3591,4373,3497,1393,1,19,107,455,1469,3713 %N A208610 Triangle of coefficients of polynomials u(n,x) jointly generated with A208611; see the Formula section. %F A208610 u(n,x)=u(n-1,x)+x*v(n-1,x), %F A208610 v(n,x)=(x+1)*u(n-1,x)+2x*v(n-1,x)+1, %F A208610 where u(1,x)=1, v(1,x)=1. %e A208610 First five rows: %e A208610 1 %e A208610 1...1 %e A208610 1...3...3 %e A208610 1...5...9...7 %e A208610 1...7...17...25...17 %e A208610 First five polynomials u(n,x): %e A208610 1 %e A208610 1 + x %e A208610 1 + 3x + 3x^2 %e A208610 1 + 5x + 9x^2 + 7x^3 %e A208610 1 + 7x + 17x^2 + 25x^3 + 17x^4 %t A208610 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A208610 u[n_, x_] := u[n - 1, x] + x*v[n - 1, x]; %t A208610 v[n_, x_] := (x + 1)*u[n - 1, x] + 2 x*v[n - 1, x] + 1; %t A208610 Table[Expand[u[n, x]], {n, 1, z/2}] %t A208610 Table[Expand[v[n, x]], {n, 1, z/2}] %t A208610 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A208610 TableForm[cu] %t A208610 Flatten[%] (* A208610 *) %t A208610 Table[Expand[v[n, x]], {n, 1, z}] %t A208610 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A208610 TableForm[cv] %t A208610 Flatten[%] (* A208611 *) %Y A208610 Cf. A208611. %K A208610 nonn,tabl %O A208610 1,5 %A A208610 _Clark Kimberling_, Mar 01 2012