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.

A130303 A130296 * A000012.

Original entry on oeis.org

1, 3, 1, 5, 2, 1, 7, 3, 2, 1, 9, 4, 3, 2, 1, 11, 5, 4, 3, 2, 1, 13, 6, 5, 4, 3, 2, 1, 15, 7, 6, 5, 4, 3, 2, 1, 17, 8, 7, 6, 5, 4, 3, 2, 1, 19, 9, 8, 7, 6, 5, 4, 3, 2, 1
Offset: 1

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Author

Gary W. Adamson, May 20 2007

Keywords

Examples

			1;
3, 1;
5, 2, 1;
7, 3, 2, 1;
9, 4, 3, 2, 1;
11, 5, 4, 3, 2, 1;
13, 6, 5, 4, 3, 2, 1;
15, 7, 6, 5, 4, 3, 2, 1;
17, 8, 7, 6, 5, 4, 3, 2, 1;
19, 9, 8, 7, 6, 5, 4, 3, 2, 1;
		

References

  • H. S. M. Coxeter, Regular Polytopes, 3rd ed., Dover, NY, 1973, pp 159-162

Crossrefs

Cf. A130296, A000012, A034856 (row sums), A130302 (commuted matrix product)

Programs

  • Mathematica
    Clear[e, n, k];
    e[n_, 0] := 2*n - 1;
    e[n_, k_] := 0 /; k >= n;
    e[n_, k_] := (e[n - 1, k]*e[n, k - 1] + 1)/e[n - 1, k - 1];
    Table[Table[e[n, k], {k, 0, n - 1}], {n, 1, 10}];
    Flatten[%]

Formula

A130296 * A000012 as infinite lower triangular matrices. (1,3,5,...) as the left border; (1,2,3,...) in all other columns.
e(n,k)= (e(n - 1, k)*e(n, k - 1) + 1)/e(n - 1, k - 1)

Extensions

Additional comments from Roger L. Bagula and Gary W. Adamson, Mar 28 2009