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.

A181417 Irregular triangle T(n,k) = binomial(n-1,m-1)*m!*A036040(n,k), where m=A036043(n,k).

Original entry on oeis.org

1, 1, 2, 1, 12, 6, 1, 24, 18, 108, 24, 1, 40, 80, 360, 540, 960, 120, 1, 60, 150, 100, 900, 3600, 900, 4800, 10800, 9000, 720, 1, 84, 252, 420, 1890, 9450, 6300, 9450, 16800, 100800, 50400, 63000, 189000, 90720, 5040, 1, 112, 392, 784, 490, 3528, 21168, 35280, 26460, 35280, 47040, 352800, 235200, 705600, 88200, 294000, 2352000, 1764000, 846720, 3175200, 987840, 40320, 1, 144, 576, 1344, 2016, 6048, 42336
Offset: 1

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Author

Alford Arnold, Oct 22 2010

Keywords

Comments

This is a refinement of the triangle A048743.
Row n has A000041(n) elements.
The sequence can be derived by expanding A007318 and A000142 and using A036040.
For example, row four can be derived using
(1 3 3 3 1) times (1 2 2 6 24) times (1 4 3 6 1) = (1 24 18 108 24)

Examples

			The table begins:
1
1...2
1..12...6
1..24..18..108..24
		

Crossrefs

Cf. A045531 (row sums), A048743, A007318, A036040.

Extensions

Row 6 onwards and definition by R. J. Mathar, Feb 12 2013