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.

A208611 Triangle of coefficients of polynomials v(n,x) jointly generated with A208610; see the Formula section.

Original entry on oeis.org

1, 2, 3, 2, 6, 7, 2, 8, 18, 17, 2, 10, 30, 52, 41, 2, 12, 44, 102, 146, 99, 2, 14, 60, 170, 328, 402, 239, 2, 16, 78, 258, 610, 1014, 1090, 577, 2, 18, 98, 368, 1016, 2076, 3044, 2920, 1393, 2, 20, 120, 502, 1572, 3756, 6792, 8932, 7746, 3363, 2, 22, 144
Offset: 1

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Author

Clark Kimberling, Mar 01 2012

Keywords

Examples

			First five rows:
1
2...3
2...6....7
2...8....18...17
2...10...30...52...41
First five polynomials v(n,x):
1
2 + 3x
2 + 6x + 7x^2
2 + 8x + 18x^2 + 17x^3
2 + 10x + 30x^2 + 52x^3 + 41x^4
		

Crossrefs

Cf. A208610.

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 + 1)*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[%]  (* A208610 *)
    Table[Expand[v[n, x]], {n, 1, z}]
    cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
    TableForm[cv]
    Flatten[%]  (* A208611 *)

Formula

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