A116539 Number of zero-one matrices with n ones and no zero rows or columns and with distinct rows, up to permutation of rows.
1, 1, 2, 7, 28, 134, 729, 4408, 29256, 210710, 1633107, 13528646, 119117240, 1109528752, 10889570768, 112226155225, 1210829041710, 13640416024410, 160069458445202, 1952602490538038, 24712910192430620, 323964329622503527, 4391974577299578248, 61488854148194151940
Offset: 0
Keywords
Examples
From _Gus Wiseman_, Dec 18 2018: (Start) The a(3) = 7 edge-sets: {{1,2,3}} {{1},{1,2}} {{2},{1,2}} {{1},{2,3}} {{2},{1,3}} {{3},{1,2}} {{1},{2},{3}} Inequivalent representatives of the a(4) = 28 0-1 matrices: [1111] . [100][1000][010][0100][001][0010][0001][110][110][1100][101][1010][1001] [111][0111][111][1011][111][1101][1110][101][011][0011][011][0101][0110] . [10][100][100][1000][100][100][1000][1000][010][010][0100][0100][0010] [01][010][010][0100][001][001][0010][0001][001][001][0010][0001][0001] [11][101][011][0011][110][011][0101][0110][110][101][1001][1010][1100] . [1000] [0100] [0010] [0001] (End)
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..300
- P. J. Cameron, T. Prellberg and D. Stark, Asymptotics for incidence matrix classes , arXiv:math/0510155 [math.CO], 2005-2006.
- M. Klazar, Extremal problems for ordered hypergraphs, arXiv:math/0305048 [math.CO], 2003.
Crossrefs
Programs
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Maple
b:= proc(n, i, k) b(n, i, k):=`if`(n=0, 1, `if`(i<1, 0, add(b(n-i*j, min(n-i*j, i-1), k)*binomial(binomial(k, i), j), j=0..n/i))) end: a:= n-> add(add(b(n$2, i)*(-1)^(k-i)*binomial(k, i), i=0..k), k=0..n): seq(a(n), n=0..23); # Alois P. Heinz, Sep 13 2019
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Mathematica
b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1, 0, Sum[b[n - i*j, Min[n - i*j, i - 1], k]*Binomial[Binomial[k, i], j], {j, 0, n/i}]]]; a[n_] := Sum[Sum[b[n, n, i]*(-1)^(k-i)*Binomial[k, i], {i, 0, k}], {k, 0, n}]; a /@ Range[0, 23] (* Jean-François Alcover, Feb 25 2020, after Alois P. Heinz *)
Extensions
a(0)=1 prepended and more terms added by Alois P. Heinz, Sep 13 2019
Comments