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.

A193607 Augmentation of the triangle A011973. See Comments.

Original entry on oeis.org

1, 1, 1, 1, 4, 2, 1, 9, 20, 7, 1, 16, 80, 131, 37, 1, 25, 220, 806, 1085, 265, 1, 36, 490, 3130, 9360, 10952, 2402, 1, 49, 952, 9325, 48224, 124498, 130852, 26371, 1, 64, 1680, 23317, 183569, 813886, 1876101, 1809430, 340272
Offset: 0

Views

Author

Clark Kimberling, Jul 31 2011

Keywords

Comments

For an introduction to the unary operation "augmentation" as applied to triangular arrays or sequences of polynomials, see A193091.
(col 2): A000290 (the squares)
(col 3)= 2*A002419

Examples

			First five rows of A193607:
1
1...1
1...4....2
1...9....20...7
1...16...80...131...37
		

Crossrefs

Programs

  • Mathematica
    p[n_, k_] := Binomial[2 n - k, k];
    Table[p[n, k], {n, 0, 7}, {k, 0, n}]  (* A011973 *)
    m[n_] := Table[If[i <= j, p[n + 1 - i, j - i], 0], {i, n}, {j, n + 1}]
    TableForm[m[4]]
    w[0, 0] = 1; w[1, 0] = p[1, 0]; w[1, 1] = p[1, 1];
    v[0] = w[0, 0]; v[1] = {w[1, 0], w[1, 1]};
    v[n_] := v[n - 1].m[n]
    TableForm[Table[v[n], {n, 0, 9}]] (* A193607 *)
    Flatten[Table[v[n], {n, 0, 8}]]