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.

A130469 Triangular array read by rows: T(j,k) = k*(j-k)! for k < j, T(j,k) = 1 for k = j; 1 <= k <= j.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 6, 4, 3, 1, 24, 12, 6, 4, 1, 120, 48, 18, 8, 5, 1, 720, 240, 72, 24, 10, 6, 1, 5040, 1440, 360, 96, 30, 12, 7, 1, 40320, 10080, 2160, 480, 120, 36, 14, 8, 1, 362880, 80640, 15120, 2880, 600, 144, 42, 16, 9, 1, 3628800, 725760, 120960, 20160, 3600
Offset: 1

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Author

Klaus Brockhaus, May 28 2007

Keywords

Comments

T is also defined in A129867, which gives row sums of T.

Examples

			First seven rows of T are
[ 1 ]
[ 1, 1 ]
[ 2, 2, 1 ]
[ 6, 4, 3, 1 ]
[ 24, 12, 6, 4, 1 ]
[ 120, 48, 18, 8, 5, 1 ]
[ 720, 240, 72, 24, 10, 6, 1 ]
		

Crossrefs

Cf. A129867, A130470 (antidiagonal sums), A130471 (first differences of antidiagonal sums).

Programs

  • Magma
    m:=11; &cat[ [ k*Factorial(j-k): k in [1..j-1] ] cat [ 1 ]: j in [1..m] ];