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A116540 Number of zero-one matrices with n ones and no zero rows or columns, up to permutation of rows. 40
1, 1, 3, 10, 41, 192, 1025, 6087, 39754, 282241, 2159916, 17691161, 154192692, 1423127819, 13851559475, 141670442163, 1517880400352, 16989834719706, 198191448685735, 2404300796114642, 30273340418567819, 394948562421362392, 5330161943597341380, 74307324695105372519 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
Also number of normal set multipartitions of weight n. These are defined as multisets of sets that together partition a normal multiset of weight n, where a multiset is normal if it spans an initial interval of positive integers. Set multipartitions are involved in the expansion of elementary symmetric functions in terms of augmented monomial symmetric functions. - Gus Wiseman, Oct 22 2015
LINKS
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.
EXAMPLE
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}.
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
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 *)
PROG
(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
CROSSREFS
Row sums of A327117.
Sequence in context: A140046 A260772 A325059 * A236407 A000248 A245504
KEYWORD
nonn
AUTHOR
Vladeta Jovovic, Mar 27 2006
EXTENSIONS
a(0)=1 prepended and more terms added by Alois P. Heinz, Sep 13 2019
STATUS
approved

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Last modified May 20 23:09 EDT 2024. Contains 372720 sequences. (Running on oeis4.)