A116540 Number of zero-one matrices with n ones and no zero rows or columns, up to permutation of rows.
1, 1, 3, 10, 41, 192, 1025, 6087, 39754, 282241, 2159916, 17691161, 154192692, 1423127819, 13851559475, 141670442163, 1517880400352, 16989834719706, 198191448685735, 2404300796114642, 30273340418567819, 394948562421362392, 5330161943597341380, 74307324695105372519
Offset: 0
Keywords
Examples
The a(3) = 10 normal set multipartitions are: {1,1,1}, {1,12}, {1,1,2}, {2,12}, {1,2,2}, {123}, {1,23}, {2,13}, {3,12}, {1,2,3}.
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..230
- 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.
- Gus Wiseman, Four symmetric function identities
Programs
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Maple
b:= proc(n, i, k) option remember; `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-1, 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..24); # Alois P. Heinz, Sep 13 2019
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Mathematica
MSOSA[s_List] := MSOSA[s] = If[Length[s] === 0, {{}}, Module[{sbs, fms}, sbs = Rest[Subsets[Union[s]]]; fms = Function[r, Append[#, r] & /@ MSOSA[Fold[DeleteCases[#1, #2, {1}, 1] &, s, r]]] /@ sbs; Select[Join @@ fms, OrderedQ] ]]; mmallnorm[n_Integer] := Function[s, Array[Count[s, y_ /; y <= #] + 1 &, n]] /@ Subsets[Range[n - 1] + 1]; Array[Plus @@ Length /@ MSOSA /@ mmallnorm[#] &, 9] (* Gus Wiseman, Oct 22 2015 *)
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PARI
R(n, k)={Vec(-1 + 1/prod(j=1, k, (1 - x^j + O(x*x^n))^binomial(k, j) ))} seq(n) = {concat([1], sum(k=1, n, R(n, k)*sum(r=k, n, binomial(r, k)*(-1)^(r-k)) ))} \\ Andrew Howroyd, Sep 23 2023
Extensions
a(0)=1 prepended and more terms added by Alois P. Heinz, Sep 13 2019
Comments