A104600 Number of matrices of any size up to column permutations, with n different elements, zero elsewhere and with no zero row or column.
1, 1, 5, 49, 795, 18881, 611193, 25704253, 1356235163, 87419692453, 6741175388313, 611464105166993, 64336296019640307, 7760748741918246361, 1062626712168331953737, 163738827988386433177093, 28181351778805732986601035, 5382075236937341624838444077
Offset: 0
Keywords
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..274
- M. Maia and M. Mendez, On the arithmetic product of combinatorial species
Programs
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Maple
b:= proc(n, k) option remember; `if`(n=0, 1, add(k!/(k-j)! *binomial(n-1, j-1)*b(n-j, k), j=1..min(k, n))) end: a:= n-> add(add(b(n, k-i)*(-1)^i*binomial(k, i), i=0..k), k=0..n): seq(a(n), n=0..21); # Alois P. Heinz, Sep 03 2019
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Mathematica
Table[Sum[StirlingS1[n,k] * Sum[StirlingS2[k,j]*j!,{j,0,k}] * BellB[k],{k,0,n}],{n,0,20}] (* Vaclav Kotesovec, May 03 2015 *) Table[1/(2*E) * Sum[Sum[Product[r*s-k,{k,0,n-1}] / (2^r s!),{r,0,Infinity}],{s,0,Infinity}],{n,0,10}] (* Vaclav Kotesovec, May 03 2015 *)
Formula
(1/(2e)) * Sum{r, s>=0, (rs)_n / [2^r s! ] }, where (m)_n is the falling factorial m * (m-1) * ... * (m-n+1).
E.g.f.: exp(-1)*sum(exp((1+x)^n)/2^(n+1),n=0..infinity). - Vladeta Jovovic, Sep 24 2006
exp(-1)*sum(1/(2-(1+x)^n)/n!,n=0..infinity) is also e.g.f. - Vladeta Jovovic, Oct 09 2006
Extensions
Corrected by Vladeta Jovovic, Sep 08 2006
Offset corrected by Vaclav Kotesovec, May 03 2015