cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A116539 Number of zero-one matrices with n ones and no zero rows or columns and with distinct rows, up to permutation of rows.

Original entry on oeis.org

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

Views

Author

Vladeta Jovovic, Mar 27 2006

Keywords

Comments

Also the number of labeled hypergraphs spanning an initial interval of positive integers with edge-sizes summing to n. - Gus Wiseman, Dec 18 2018

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)
		

Crossrefs

Binary matrices with distinct rows and columns, various versions: A059202, A088309, A088310, A088616, A089673, A089674, A093466, A094000, A094223, A116532, A116539, A181230, A259763
Row sums of A326914 and of A326962.

Programs

  • 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
  • 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