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.

Showing 1-3 of 3 results.

A179972 Irregular table T(n,k) = A178886(n,k)/A048996(n,k) read by rows.

Original entry on oeis.org

1, 1, 1, 2, 1, 1, 6, 2, 2, 1, 1, 24, 6, 6, 2, 2, 1, 1, 120, 24, 24, 24, 6, 6, 6, 2, 2, 1, 1, 720, 120, 120, 120, 24, 24, 24, 24, 6, 6, 6, 2, 2, 1, 1, 5040, 720, 720, 720, 720, 120, 120, 120, 120, 120, 24, 24, 24, 24, 24, 6, 6, 6, 2, 2, 1, 1, 40320
Offset: 1

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Author

Alford Arnold, Aug 04 2010

Keywords

Comments

Row n has A000041(n) terms.
Consider the five partitions of the number 4:
4 3+1 2+2 2+1+1 and 1+1+1+1
rewriting as 4000 3100 2200 2110 and 1111
then a(n) counts the ways that the zeros can be permuted:
6,2,2,1,1
agreeing with the factorial of the difference between A036042 and A036043.

Examples

			Row four of A178886 begins: 6 4 2 3 1
Row four of A048996 begins: 1 2 1 3 1
so,
Row four of A179972 begins: 6 2 2 1 1
Triangle T(n,k) begins:
    1;
    1,  1;
    2,  1,  1;
    6,  2,  2,  1, 1;
   24,  6,  6,  2, 2, 1, 1;
  120, 24, 24, 24, 6, 6, 6, 2, 2, 1, 1;
  ...
		

Crossrefs

Cf. A178886, A048996, A036042, A036043, A179973 (row sums).

Formula

T(n,k) = ( A036042(n,k) - A036043(n,k))!.
T(n,k) = n!/A178888(n,k). - R. J. Mathar, Mar 03 2011

A178883 Multiply, cell by cell, the sequences A096162, A048996 and A178886.

Original entry on oeis.org

1, 1, 2, 2, 4, 6, 6, 8, 4, 18, 24, 24, 24, 24, 36, 36, 96, 120, 120, 96, 96, 48, 108, 216, 36, 192, 288, 600, 720, 720, 480, 480, 480, 432, 864, 432, 432, 576, 1728, 576, 1200, 2400, 4320, 5040
Offset: 1

Views

Author

Alford Arnold, Jun 23 2010

Keywords

Comments

Shape sequence for this irregular table is A000041.

Examples

			Row 3: (1,1,6) times (1,2,1) times (2,2,1) yielding (2,4,6) with row sum 12 agreeing with 1,3,12,60,360,...; cf. A001700.
		

Crossrefs

Cf. A162608, A001710 (row sums). - Alford Arnold, Sep 28 2010

Extensions

More terms from Alford Arnold, Sep 28 2010

A179236 Irregular triangle T(n,k) = A096162(n,k)* A036040(n,k)* A048996(n,k)*A098546(n,k)* A178886(n,k) read by rows, 1<=k<=A000041(n).

Original entry on oeis.org

1, 2, 2, 6, 36, 6, 24, 192, 72, 432, 24, 120, 1200, 2400, 3600, 5400, 4800, 120, 720, 8640, 21600, 7200, 32400, 259200, 10800, 57600, 194400, 54000, 720, 5040, 70560, 211680, 352800, 317520, 3175200, 1058400, 1587600, 705600, 12700800, 2116800, 882000, 5292000, 635040, 5040, 40320, 645120, 2257920, 4515840
Offset: 1

Views

Author

Alford Arnold, Jul 04 2010

Keywords

Examples

			The factor sequences begin
1..1..2..1..1..6
1..1..1..1..3..1
1..1..1..1..2..1
1..2..1..3..3..1
1..1..1..2..2..1
so the present sequence begins
1..2..2..6..36..6
		

Crossrefs

Cf. A000041 (row lengths) A096161 A000110 A000079 A098545 A000522 A179235 (row sums)
Showing 1-3 of 3 results.