cp's OEIS Frontend

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.

A208336 Triangle of coefficients of polynomials u(n,x) jointly generated with A208337; see the Formula section.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 1, 3, 5, 3, 1, 4, 9, 10, 5, 1, 5, 14, 22, 20, 8, 1, 6, 20, 40, 51, 38, 13, 1, 7, 27, 65, 105, 111, 71, 21, 1, 8, 35, 98, 190, 256, 233, 130, 34, 1, 9, 44, 140, 315, 511, 594, 474, 235, 55, 1, 10, 54, 192, 490, 924, 1295, 1324, 942, 420, 89, 1, 11
Offset: 1

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Author

Clark Kimberling, Feb 26 2012

Keywords

Comments

coef. of x^(n-1) in u(n,x): A000045(n), Fibonacci numbers
coef. of x^(n-1) in v(n,x): A000045(n+1)
row sums, u(n,1): A000129
row sums, v(n,1): A001333
alternating row sums, u(n,-1): 1,0,1,0,1,0,1,0,1,0,...
alternating row sums, v(n,-1): 1,-1,1,-1,1,-1,1,-1,...

Examples

			First five rows:
1
1...1
1...2...2
1...3...5...3
1...4...9...10...5
First five polynomials u(n,x):
1
1 + x
1 + 2x + 2x^2
1 + 3x + 5x^2 + 3x^3
1 + 4x + 9x^2 + 10x^3 + 5x^4
		

Crossrefs

Apart from offsets the same as A038137.
Cf. A208337.

Programs

  • Mathematica
    u[1, x_] := 1; v[1, x_] := 1; z = 13;
    u[n_, x_] := u[n - 1, x] + x*v[n - 1, x];
    v[n_, x_] := (x + 1)*u[n - 1, x] + x*v[n - 1, x];
    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[%]    (* A208336 *)
    Table[Expand[v[n, x]], {n, 1, z}]
    cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
    TableForm[cv]
    Flatten[%]    (* A208337 *)
    Table[u[n, x] /. x -> 1, {n, 1, z}] (* u row sums *)
    Table[v[n, x] /. x -> 1, {n, 1, z}] (* v row sums *)
    Table[u[n, x] /. x -> -1, {n, 1, z}](* u alt. row sums *)
    Table[v[n, x] /. x -> -1, {n, 1, z}](* v alt. row sums *)

Formula

u(n,x)=u(n-1,x)+x*v(n-1,x),
v(n,x)=(x+1)*u(n-1,x)+x*v(n-1,x),
where u(1,x)=1, v(1,x)=1.
T(n,k) = A038137(n-1,k). - Philippe Deléham, Apr 05 2012