A104602 Number of square (0,1)-matrices with exactly n entries equal to 1 and no zero row or columns.
1, 1, 2, 10, 70, 642, 7246, 97052, 1503700, 26448872, 520556146, 11333475922, 270422904986, 7016943483450, 196717253145470, 5925211960335162, 190825629733950454, 6543503207678564364, 238019066600097607402, 9153956822981328930170, 371126108428565106918404
Offset: 0
Keywords
Examples
From _Gus Wiseman_, Nov 14 2018: (Start) The a(3) = 10 matrices: [1 1] [1 1] [1 0] [0 1] [1 0] [0 1] [1 1] [1 1] . [1 0 0] [1 0 0] [0 1 0] [0 1 0] [0 0 1] [0 0 1] [0 1 0] [0 0 1] [1 0 0] [0 0 1] [1 0 0] [0 1 0] [0 0 1] [0 1 0] [0 0 1] [1 0 0] [0 1 0] [1 0 0] (End)
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..400
- H. Cheballah, S. Giraudo, R. Maurice, Combinatorial Hopf algebra structure on packed square matrices, arXiv preprint arXiv:1306.6605 [math.CO], 2013-2015.
- M. Maia and M. Mendez, On the arithmetic product of combinatorial species, arXiv:math/0503436 [math.CO], 2005.
Crossrefs
Programs
-
Mathematica
Table[1/n!*Sum[StirlingS1[n,k]*Sum[(m!)^2*StirlingS2[k, m]^2, {m, 0, k}],{k,0,n}],{n,1,20}] (* Vaclav Kotesovec, May 07 2014 *) Table[Length[Select[Subsets[Tuples[Range[n],2],{n}],Union[First/@#]==Union[Last/@#]==Range[Max@@First/@#]&]],{n,5}] (* Gus Wiseman, Nov 14 2018 *)
Formula
a(n) = (1/n!)*Sum_{k=0..n} Stirling1(n,k)*A048144(k). - Vladeta Jovovic, Mar 25 2006
G.f.: Sum_{n>=0} Sum_{j=0..n} (-1)^(n-j)*binomial(n,j)*((1+x)^j-1)^n. - Vladeta Jovovic, Mar 25 2006
a(n) ~ c * n! / (sqrt(n) * (log(2))^(2*n)), where c = 0.28889864564457451375789435201798... . - Vaclav Kotesovec, May 07 2014
In closed form, c = 1 / (log(2) * 2^(log(2)/2+2) * sqrt(Pi*(1-log(2)))). - Vaclav Kotesovec, May 03 2015
G.f.: Sum_{n>=0} ((1+x)^n - 1)^n / (1+x)^(n*(n+1)). - Paul D. Hanna, Mar 26 2018
Extensions
More terms from Vladeta Jovovic, Mar 25 2006
a(0)=1 prepended by Alois P. Heinz, Jan 14 2015
Comments