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.

A210551 Triangle of coefficients of polynomials v(n,x) jointly generated with A172431; see the Formula section.

Original entry on oeis.org

1, 3, 1, 5, 6, 1, 7, 15, 10, 1, 9, 28, 35, 15, 1, 11, 45, 84, 70, 21, 1, 13, 66, 165, 210, 126, 28, 1, 15, 91, 286, 495, 462, 210, 36, 1, 17, 120, 455, 1001, 1287, 924, 330, 45, 1, 19, 153, 680, 1820, 3003, 3003, 1716, 495, 55, 1, 21, 190, 969, 3060, 6188
Offset: 1

Views

Author

Clark Kimberling, Mar 22 2012

Keywords

Comments

Row sums: -1+odd-indexed Fibonacci numbers
Alternating row sums: 1,2,0,1,2,0,1,2,0,...
For a discussion and guide to related arrays, see A208510.

Examples

			From _Paul Weisenhorn_, May 17 2020 : (Start)
First five rows of v(n.x):
  1
  3   1
  5   6   1
  7  15  10   1
  9  28  35  15  1
First three polynomials v(n,x): 1, 3 + x, 5 + 6x + x^2. (End)
From _Paul Weisenhorn_, May 14 2020: (Start)
First five rows of u(n,x):
  1
  1  2
  1  4   3
  1  6  10   4
  1  8  21  20  5
First three polynomials u(n,x): 1, 1 + 2x, 1 + 4x + 3x^2. (End)
		

Crossrefs

Programs

  • Mathematica
    u[1, x_] := 1; v[1, x_] := 1; z = 16;
    u[n_, x_] := x*u[n - 1, x] + x*v[n - 1, x] + 1;
    v[n_, x_] := u[n - 1, x] + (x + 1)*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[%]    (* A172431 *)
    Table[Expand[v[n, x]], {n, 1, z}]
    cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
    TableForm[cv]
    Flatten[%]    (* A210551 *)

Formula

u(n,x)=x*u(n-1,x)+x*v(n-1,x)+1,
v(n,x)=u(n-1,x)+(x+1)*v(n-1,x)+1
where u(1,x)=1, v(1,x)=1.