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 A208524 #6 Mar 30 2012 18:58:13 %S A208524 1,1,1,1,3,3,1,6,10,5,1,10,22,23,11,1,15,40,65,60,21,1,21,65,145,195, %T A208524 137,43,1,28,98,280,490,518,322,85,1,36,140,490,1050,1484,1372,723, %U A208524 171,1,45,192,798,2016,3570,4368,3447,1624,341,1,55,255,1230,3570 %N A208524 Triangle of coefficients of polynomials u(n,x) jointly generated with A208525; see the Formula section. %C A208524 Alternating row sums: 1,0,1,0,1,0,1,0,... %F A208524 u(n,x)=u(n-1,x)+x*v(n-1,x), %F A208524 v(n,x)=2x*u(n-1,x)+(x+1)*v(n-1,x)+1, %F A208524 where u(1,x)=1, v(1,x)=1. %e A208524 First five rows: %e A208524 1 %e A208524 1...1 %e A208524 1...3....3 %e A208524 1...6....10...5 %e A208524 1...10...22...23...11 %e A208524 First five polynomials u(n,x): %e A208524 1 %e A208524 1 + x %e A208524 1 + 3x + 3x^2 %e A208524 1 + 6x + 10x^2 + 5x^3 %e A208524 1 + 10x + 22x^2 + 23x^3 + 11x^4 %t A208524 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A208524 u[n_, x_] := u[n - 1, x] + x*v[n - 1, x]; %t A208524 v[n_, x_] := 2 x*u[n - 1, x] + (x + 1)*v[n - 1, x] + 1; %t A208524 Table[Expand[u[n, x]], {n, 1, z/2}] %t A208524 Table[Expand[v[n, x]], {n, 1, z/2}] %t A208524 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A208524 TableForm[cu] %t A208524 Flatten[%] (* A208524 *) %t A208524 Table[Expand[v[n, x]], {n, 1, z}] %t A208524 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A208524 TableForm[cv] %t A208524 Flatten[%] (* A208525 *) %t A208524 Table[u[n, x] /. x -> 1, {n, 1, z}] (*A060816*) %t A208524 Table[v[n, x] /. x -> 1, {n, 1, z}] (*|A084244|*) %t A208524 Table[u[n, x] /. x -> -1, {n, 1, z}](*alt. row sums*) %t A208524 Table[v[n, x] /. x -> -1, {n, 1, z}](*alt. row sums*) %Y A208524 Cf. A208525. %K A208524 nonn,tabl %O A208524 1,5 %A A208524 _Clark Kimberling_, Feb 29 2012