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.

A208512 Triangle of coefficients of polynomials v(n,x) jointly generated with A208511; see the Formula section.

Original entry on oeis.org

1, 2, 2, 2, 5, 4, 2, 7, 12, 8, 2, 9, 21, 28, 16, 2, 11, 32, 58, 64, 32, 2, 13, 45, 101, 152, 144, 64, 2, 15, 60, 159, 296, 384, 320, 128, 2, 17, 77, 234, 513, 824, 944, 704, 256, 2, 19, 96, 328, 822, 1554, 2208, 2272, 1536, 512, 2, 21, 117, 443, 1244, 2685
Offset: 1

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Author

Clark Kimberling, Feb 28 2012

Keywords

Comments

Alternating row sums are signed Fibonacci numbers (A000045).

Examples

			First five rows:
1
2...2
2...5...4
2...7...12...8
2...9...21...28...16
First five polynomials v(n,x):
1
2 + 2x
2 + 5x + 4x^2
2 + 7x + 12x^2 + 8x^3
2 + 9x + 21x^2 + 28x^3 + 16x^4
		

Crossrefs

Cf. A208511.

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_] := u[n - 1, x] + 2 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[%]  (* A208511 *)
    Table[Expand[v[n, x]], {n, 1, z}]
    cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
    TableForm[cv]
    Flatten[%]    (* A208512 *)

Formula

u(n,x)=u(n-1,x)+x*v(n-1,x),
v(n,x)=u(n-1,x)+2x*v(n-1,x)+1,
where u(1,x)=1, v(1,x)=1.