login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A180512 Triangle of the number of alternating sign matrices according to the number of -1's 0
1, 2, 6, 1, 24, 16, 2, 120, 200, 94, 14, 1, 720, 2400, 2684, 1284, 310, 36, 2, 5040, 29400, 63308, 66158, 38390, 13037, 2660, 328, 26, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The first column is the factorial, A000142.

The second column forms coefficients of Laguerre polynomials, A001810.

LINKS

Table of n, a(n) for n=1..29.

FindStat - Combinatorial Statistic Finder, The number of entries equal to negative one in the alternating sign matrix

Wikipedia, Alternating Sign Matrix

EXAMPLE

In triangular format, the numbers of ASMs is as follows:

n=1:1

n=2:2

n=3:6,1

n=4:24,16,2

n=5:120,200,94,14,1

n=6:720,2400,2684,1284,310,36,2

n=7:5040,29400,63308,66158,38390,13037,2660,328,26,1

CROSSREFS

Row sums are A005130.

Sequence in context: A281046 A281521 A281635 * A132181 A291646 A027642

Adjacent sequences:  A180509 A180510 A180511 * A180513 A180514 A180515

KEYWORD

nonn,hard,tabf,changed

AUTHOR

Arvind Ayyer, Jan 20 2011

EXTENSIONS

T(7, 7) corrected by Arvind Ayyer, Feb 12 2018

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 20 12:28 EST 2018. Contains 299379 sequences. (Running on oeis4.)