

A110058


Number of nonnegative integer matrices of order n for which all row and column sums equal n.


3



1, 1, 3, 55, 10147, 22069251, 602351808741, 215717608046511873, 1046591482728407939338275, 70417932475495769964322670258947, 66880713903767740581650957184096513655153, 909176713758393122455793478657031533216492953328933, 178876969166665269546249744608783223036842010760723370462856181, 514016665650183402309555825250370336139392333285719205357202846243695510965
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OFFSET

0,3


COMMENTS

Computed by a method that involves summing a multivariate generating function over roots of unity.


LINKS

Table of n, a(n) for n=0..13.
E. R. Canfield, B. D. McKay, Asymptotic enumeration of integer matrices with large equal row and column sums, Combinatorica 30 (6) (2010) 655680


FORMULA

log a(n) = 2(log 2)*n^2  n*(log n)  n*(log 4*Pi) + (log n) + O(1).  Igor Pak, May 15 2019


EXAMPLE

a(2) = 3 due to the matrices [1,1  1,1], [0,2  2,0] and [2,0  0,2].


PROG

(Sage)
from sage.combinat.integer_matrices import IntegerMatrices
[IntegerMatrices([n]*n, [n]*n).cardinality() for n in (0..6)] # Freddy Barrera, Dec 27 2018


CROSSREFS

Cf. A058407, A058410, A058391.
Main diagonal of A257493 and A333901.
Sequence in context: A172932 A172950 A172962 * A083869 A290773 A119188
Adjacent sequences: A110055 A110056 A110057 * A110059 A110060 A110061


KEYWORD

nonn


AUTHOR

Brendan McKay, Sep 04 2005


EXTENSIONS

a(0)=1 prepended by Alois P. Heinz, Apr 26 2015


STATUS

approved



