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.

A208519 Triangle of coefficients of polynomials v(n,x) jointly generated with A208518; see the Formula section.

Original entry on oeis.org

1, 2, 2, 3, 5, 3, 4, 9, 11, 5, 5, 14, 26, 23, 8, 6, 20, 50, 65, 45, 13, 7, 27, 85, 145, 150, 86, 21, 8, 35, 133, 280, 385, 329, 160, 34, 9, 44, 196, 490, 840, 952, 692, 293, 55, 10, 54, 276, 798, 1638, 2310, 2232, 1413, 529, 89, 11, 65, 375, 1230, 2940, 4956
Offset: 1

Views

Author

Clark Kimberling, Feb 28 2012

Keywords

Comments

coefficient of x^(n-1): Fibonacci(n+1) = A000045(n+1)
col 1: A000027
col 2: A000096
col 3: A051925
row sums: A002878 (bisection of Lucas sequence)
alternating row sums: A000045(n-2), Fibonacci numbers

Examples

			First five rows:
1
2...2
3...5....3
4...9....11...5
5...14...26...23...8
First five polynomials v(n,x):
1
2 + 2x
3 + 5x + 3x^2
4 + 9x + 11x^2 + 5x^3
5 + 14x + 26x^2 + 23x^3 + 8x^4
		

Crossrefs

Cf. A208518.

Programs

  • 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 + 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[%]   (* A208518 *)
    Table[Expand[v[n, x]], {n, 1, z}]
    cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
    TableForm[cv]
    Flatten[%]   (* A208519 *)

Formula

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