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A249042 Three-dimensional array of numbers N(r,p,m) read by triangular slices, each slice being read across rows: N(r,p,m) is the number of "r-panes in a (p,m) structure". 1
1, 1, 1, 2, 1, 3, 4, 1, 6, 6, 1, 6, 7, 7, 24, 18, 1, 14, 36, 24, 1, 10, 11, 25, 70, 46, 15, 100, 180, 96, 1, 30, 150, 240, 120, 1, 15, 16, 65, 165, 101, 90, 455, 690, 326, 31, 360, 1170, 1440, 600, 1, 62, 540, 1560, 1800, 720 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Three-dimensional arrays don't really work in the OEIS, but this one seems like it should be included. See Good-Tideman for precise definition.

LINKS

Table of n, a(n) for n=1..56.

I. J. Good, T. N. Tideman, Stirling numbers and a geometric structure from voting theory, Journal of Combinatorial Theory, Series A Volume 23, Issue 1, July 1977, Pages 34-45.

Warren D. Smith, D-dimensional orderings and Stirling numbers, October 2014.

FORMULA

There is a formula involving Stirling numbers.

EXAMPLE

The initial triangular slices are:

1

-

1

1 2

---

1

3 4

1 6 6

-----

1

6 7

7 24 18

1 14 36 24

----------

1

10 11

25 70  46

15 100 180 96

1  30  150 240 120

----------------

1

15 16

65 165 101

90 455 690  326

31 360 1170 1440 600

1  62  540  1560 1800 720

CROSSREFS

The sequence of left edges of the triangles is A008278; the bases of the triangles give A019538; the hypotenuses give A181854.

Sequence in context: A094442 A060642 A154929 * A262472 A049400 A283524

Adjacent sequences:  A249039 A249040 A249041 * A249043 A249044 A249045

KEYWORD

nonn,tabf,more

AUTHOR

N. J. A. Sloane, Oct 29 2014

EXTENSIONS

More terms from Michel Marcus, Aug 28 2015

STATUS

approved

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Last modified February 17 20:22 EST 2018. Contains 299296 sequences. (Running on oeis4.)