A208514 Triangle of coefficients of polynomials u(n,x) jointly generated with A208515; see the Formula section.
1, 1, 1, 1, 2, 2, 1, 3, 4, 3, 1, 4, 6, 7, 5, 1, 5, 8, 12, 13, 8, 1, 6, 10, 18, 24, 23, 13, 1, 7, 12, 25, 38, 46, 41, 21, 1, 8, 14, 33, 55, 78, 88, 72, 34, 1, 9, 16, 42, 75, 120, 158, 165, 126, 55, 1, 10, 18, 52, 98, 173, 255, 313, 307, 219, 89, 1, 11, 20, 63, 124, 238
Offset: 1
Examples
First five rows: 1 1...1 1...2...2 1...3...4...3 1...4...6...7...5 First five polynomials u(n,x): 1 1 + x 1 + 2x + 2x^2 1 + 3x + 4x^2 + 3x^3 1 + 4x + 6x^2 + 7x^3 + 5x^4
Crossrefs
Cf. A208515.
Programs
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Mathematica
u[1, x_] := 1; v[1, x_] := 1; z = 16; u[n_, x_] := u[n - 1, x] + x*v[n - 1, x]; v[n_, x_] := x*u[n - 1, x] + x*v[n - 1, x] + 1; Table[Expand[u[n, x]], {n, 1, z/2}] Table[Expand[v[n, x]], {n, 1, z/2}] cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; TableForm[cu] Flatten[%] (* A208514 *) Table[Expand[v[n, x]], {n, 1, z}] cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; TableForm[cv] Flatten[%] (* A208515 *)
Formula
u(n,x)=u(n-1,x)+x*v(n-1,x),
v(n,x)=x*u(n-1,x)+x*v(n-1,x)+1,
where u(1,x)=1, v(1,x)=1.
Comments