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.

A207623 Triangle of coefficients of polynomials v(n,x) jointly generated with A207622; see the Formula section.

Original entry on oeis.org

1, 2, 2, 3, 6, 4, 14, 4, 5, 28, 20, 6, 50, 64, 8, 7, 82, 164, 56, 8, 126, 364, 232, 16, 9, 184, 728, 736, 144, 10, 258, 1344, 1968, 736, 32, 11, 350, 2328, 4656, 2800, 352, 12, 462, 3828, 10032, 8800, 2144, 64, 13, 596, 6028, 20064, 24112, 9536, 832, 14
Offset: 1

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Author

Clark Kimberling, Feb 20 2012

Keywords

Comments

Column n is divisible by 2^(n-1); row n ends with 2^(n-1).
Column 2: 2*A004006.

Examples

			First five rows:
1
2...2
3...6
4...14...4
5...28...20
		

Crossrefs

Cf. A207622.

Programs

  • Mathematica
    u[1, x_] := 1; v[1, x_] := 1; z = 16;
    u[n_, x_] := u[n - 1, x] + v[n - 1, x]
    v[n_, x_] := 2 x*u[n - 1, x] + v[n - 1, x] + 1
    Table[Factor[u[n, x]], {n, 1, z}]
    Table[Factor[v[n, x]], {n, 1, z}]
    cu = Table[CoefficientList[u[n, x], x], {n, 1, z}];
    TableForm[cu]
    Flatten[%]    (* A207622 *)
    Table[Expand[v[n, x]], {n, 1, z}]
    cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
    TableForm[cv]
    Flatten[%]    (* A207623 *)

Formula

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