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.

A208340 Triangle of coefficients of polynomials v(n,x) jointly generated with A202390; see the Formula section.

Original entry on oeis.org

1, 2, 2, 3, 6, 3, 4, 13, 14, 5, 5, 24, 41, 30, 8, 6, 40, 96, 109, 60, 13, 7, 62, 196, 308, 262, 116, 21, 8, 91, 364, 743, 868, 590, 218, 34, 9, 128, 630, 1604, 2413, 2240, 1267, 402, 55, 10, 174, 1032, 3186, 5926, 7046, 5424, 2627, 730, 89, 11, 230, 1617
Offset: 1

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Author

Clark Kimberling, Feb 27 2012

Keywords

Comments

v(n,n) = F(n+1), where F=A000045, the Fibonacci numbers.
Alternating row sums of v: (1,0,0,0,0,0,0,0,...).
As triangle T(n,k) with 0 <= k <= n, it is (2, -1/2, 1/2, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (2, -1/2, -1/2, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938.

Examples

			First five rows:
  1;
  2,  2;
  3,  6,  3;
  4, 13, 14,  5;
  5, 24, 41, 30,  8;
The first five polynomials v(n,x):
  1
  2 +  2x
  3 +  6x +  3x^2
  4 + 13x + 14x^2 +  5x^3
  5 + 24x + 41x^2 + 30x^3 + 8x^4
		

Crossrefs

Cf. A202390.

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 + 1)*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[%]    (* A202390 *)
    Table[Expand[v[n, x]], {n, 1, z}]
    cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
    TableForm[cv]
    Flatten[%]    (* A208340 *)
    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+1)*v(n-1,x), where u(1,x)=1, v(1,x)=1.
From Philippe Deléham, Feb 28 2012: (Start)
As triangle T(n,k) with 0 <= k <= n:
T(n,k) = 2*T(n-1,k) + T(n-1,k-1) - T(n-2,k) + T(n-2,k-2) with T(0,0) = 1, T(1,0) = T(1,1) = 2 and T(n,k) = 0 if k < 0 or if k > n.
G.f.: (1+y*x)/(1-2*x-y*x+x^2-y^2*x^2).
Sum_{k=0..n} T(n,k)*x^k = A000007(n), A000027(n+1), A003946(n), A109115(n), A180031(n) for x = -1, 0, 1, 2, 3 respectively. (End)