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.

A193861 Mirror of the triangle A193860.

Original entry on oeis.org

1, 5, 1, 19, 7, 1, 65, 33, 9, 1, 211, 131, 51, 11, 1, 665, 473, 233, 73, 13, 1, 2059, 1611, 939, 379, 99, 15, 1, 6305, 5281, 3489, 1697, 577, 129, 17, 1, 19171, 16867, 12259, 6883, 2851, 835, 163, 19, 1, 58025, 52905, 41385, 26025, 12585, 4521, 1161
Offset: 0

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Author

Clark Kimberling, Aug 07 2011

Keywords

Comments

A193861 is obtained by reversing the rows of the triangle A193860.

Examples

			First six rows:
1
5.....1
19....7.....1
65....33....9.....1
211...131...51....11...1
665...473...233...73...13...1
		

Crossrefs

Cf. A193860.

Programs

  • Mathematica
    z = 10;
    p[n_, x_] := (2 x + 1)^n;
    q[0, x_] := 1; q[n_, x_] := x*q[n - 1, x] + 1;
    p1[n_, k_] := Coefficient[p[n, x], x^k];
    p1[n_, 0] := p[n, x] /. x -> 0;
    d[n_, x_] := Sum[p1[n, k]*q[n - 1 - k, x], {k, 0, n - 1}]
    h[n_] := CoefficientList[d[n, x], {x}]
    TableForm[Table[Reverse[h[n]], {n, 0, z}]]
    Flatten[Table[Reverse[h[n]], {n, -1, z}]]  (* A193860 *)
    TableForm[Table[h[n], {n, 0, z}]]
    Flatten[Table[h[n], {n, -1, z}]]   (* A193861  *)

Formula

Write w(n,k) for the triangle at A193860. The triangle at A193861 is then given by w(n,n-k).