A321587 Number of (0,1)-matrices with n ones, no zero rows or columns, and distinct rows.
1, 1, 3, 17, 129, 1227, 14123, 190265, 2934359, 50975647, 984801759, 20941104299, 486007744671, 12223797601887, 331190083773701, 9616356919931711, 297887922137531747, 9805965265937326129, 341827167387114704421, 12579123760272833723975, 487315396984696657840761
Offset: 0
Keywords
Examples
The a(3) = 17 matrices: [1 1 1] . [1 1] [1 1] [1 1 0] [1 0 1] [1 0] [1 0 0] [0 1 1] [0 1] [0 1 0] [0 0 1] [1 0] [0 1] [0 0 1] [0 1 0] [1 1] [0 1 1] [1 0 0] [1 1] [1 0 1] [1 1 0] . [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]
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..200
Crossrefs
Programs
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Maple
C:= binomial: b:= proc(n, i, k, p) option remember; `if`(n=0, p!, `if`(i<1, 0, add( b(n-i*j, min(n-i*j, i-1), k, p+j)*C(C(k, i), j), j=0..n/i))) end: a:= n-> add(add(b(n$2, i, 0)*(-1)^(k-i)*C(k, i), i=0..k), k=0..n): seq(a(n), n=0..21); # Alois P. Heinz, Sep 16 2019
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Mathematica
prs2mat[prs_]:=Table[Count[prs,{i,j}],{i,Union[First/@prs]},{j,Union[Last/@prs]}]; Table[Length[Select[Subsets[Tuples[Range[n],2],{n}],And[Union[First/@#]==Range[Max@@First/@#],Union[Last/@#]==Range[Max@@Last/@#],UnsameQ@@prs2mat[#]]&]],{n,5}]
Formula
a(n) ~ c * d^n * n!, where d = 1.938593839617140963759657977... and c = 0.350862127201784401195038... - Vaclav Kotesovec, Feb 05 2022
Extensions
a(7)-a(20) from Alois P. Heinz, Sep 16 2019
Comments