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.

A059674 Square array a(m,n) = binomial(max(m,n), min(m,n)) (m>=0, n>=0) read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 3, 1, 3, 1, 1, 4, 3, 3, 4, 1, 1, 5, 6, 1, 6, 5, 1, 1, 6, 10, 4, 4, 10, 6, 1, 1, 7, 15, 10, 1, 10, 15, 7, 1, 1, 8, 21, 20, 5, 5, 20, 21, 8, 1, 1, 9, 28, 35, 15, 1, 15, 35, 28, 9, 1, 1, 10, 36, 56, 35, 6, 6, 35, 56, 36, 10, 1, 1, 11, 45, 84, 70, 21, 1, 21, 70, 84
Offset: 0

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Author

Fabian Rothelius, Feb 05 2001

Keywords

Examples

			a(2,4) = binomial(max(2,4), min(2,4)) = binomial(4,2) = 6.
Square begins:
1 1 1 1 1 1 ...
1 1 2 3 4 5 ...
1 2 1 3 6 10...
1 3 3 1 4 10 ...
		

Crossrefs

Cf. A007318.

Programs

  • Mathematica
    a[m_, n_] := If[m >= n, Binomial[m, n], Binomial[n, m]]; Table[a[m-n, n], {m, 0, 12}, {n, 0, m}] // Flatten (* Jean-François Alcover, Oct 10 2012 *)

Formula

Square array equals A007318 + transpose(A007318) - I, where I denotes the infinite identity matrix. - Peter Bala, Aug 11 2015

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Feb 06 2001