%I #5 Mar 30 2012 18:58:16
%S 1,1,2,1,3,4,1,4,7,8,1,5,10,17,16,1,6,13,28,39,32,1,7,16,41,70,89,64,
%T 1,8,19,56,109,176,199,128,1,9,22,73,156,297,426,441,256,1,10,25,92,
%U 211,456,765,1020,967,512,1,11,28,113,274,657,1236,1953,2398
%N Triangle of coefficients of polynomials u(n,x) jointly generated with A210556; see the Formula section.
%C For a discussion and guide to related arrays, see A208510.
%F u(n,x)=x*u(n-1,x)+x*v(n-1,x)+1,
%F v(n,x)=2x*u(n-1,x)+v(n-1,x)+1,
%F where u(1,x)=1, v(1,x)=1.
%e First five rows:
%e 1
%e 1...2
%e 1...3...4
%e 1...4...7....8
%e 1...5...10...17...16
%e First three polynomials u(n,x): 1, 1 + 2x, 1 + 3x + 4x^2.
%t u[1, x_] := 1; v[1, x_] := 1; z = 16;
%t u[n_, x_] := x*u[n - 1, x] + x*v[n - 1, x] + 1;
%t v[n_, x_] := x*u[n - 1, x] + (x + 1)*v[n - 1, x] + 1;
%t Table[Expand[u[n, x]], {n, 1, z/2}]
%t Table[Expand[v[n, x]], {n, 1, z/2}]
%t cu = Table[CoefficientList[u[n, x], x], {n, 1, z}];
%t TableForm[cu]
%t Flatten[%] (* A208341 *)
%t Table[Expand[v[n, x]], {n, 1, z}]
%t cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
%t TableForm[cv]
%t Flatten[%] (* A210554 *)
%Y Cf. A210554, A208510.
%K nonn,tabl
%O 1,3
%A _Clark Kimberling_, Mar 22 2012