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.
%I A116539 #26 Feb 25 2020 08:14:09 %S A116539 1,1,2,7,28,134,729,4408,29256,210710,1633107,13528646,119117240, %T A116539 1109528752,10889570768,112226155225,1210829041710,13640416024410, %U A116539 160069458445202,1952602490538038,24712910192430620,323964329622503527,4391974577299578248,61488854148194151940 %N A116539 Number of zero-one matrices with n ones and no zero rows or columns and with distinct rows, up to permutation of rows. %C A116539 Also the number of labeled hypergraphs spanning an initial interval of positive integers with edge-sizes summing to n. - _Gus Wiseman_, Dec 18 2018 %H A116539 Alois P. Heinz, <a href="/A116539/b116539.txt">Table of n, a(n) for n = 0..300</a> %H A116539 P. J. Cameron, T. Prellberg and D. Stark, <a href="https://arxiv.org/abs/math/0510155">Asymptotics for incidence matrix classes </a>, arXiv:math/0510155 [math.CO], 2005-2006. %H A116539 M. Klazar, <a href="https://arxiv.org/abs/math/0305048">Extremal problems for ordered hypergraphs</a>, arXiv:math/0305048 [math.CO], 2003. %e A116539 From _Gus Wiseman_, Dec 18 2018: (Start) %e A116539 The a(3) = 7 edge-sets: %e A116539 {{1,2,3}} %e A116539 {{1},{1,2}} %e A116539 {{2},{1,2}} %e A116539 {{1},{2,3}} %e A116539 {{2},{1,3}} %e A116539 {{3},{1,2}} %e A116539 {{1},{2},{3}} %e A116539 Inequivalent representatives of the a(4) = 28 0-1 matrices: %e A116539 [1111] %e A116539 . %e A116539 [100][1000][010][0100][001][0010][0001][110][110][1100][101][1010][1001] %e A116539 [111][0111][111][1011][111][1101][1110][101][011][0011][011][0101][0110] %e A116539 . %e A116539 [10][100][100][1000][100][100][1000][1000][010][010][0100][0100][0010] %e A116539 [01][010][010][0100][001][001][0010][0001][001][001][0010][0001][0001] %e A116539 [11][101][011][0011][110][011][0101][0110][110][101][1001][1010][1100] %e A116539 . %e A116539 [1000] %e A116539 [0100] %e A116539 [0010] %e A116539 [0001] %e A116539 (End) %p A116539 b:= proc(n, i, k) b(n, i, k):=`if`(n=0, 1, `if`(i<1, 0, add(b(n-i*j, %p A116539 min(n-i*j, i-1), k)*binomial(binomial(k, i), j), j=0..n/i))) %p A116539 end: %p A116539 a:= n-> add(add(b(n$2, i)*(-1)^(k-i)*binomial(k, i), i=0..k), k=0..n): %p A116539 seq(a(n), n=0..23); # _Alois P. Heinz_, Sep 13 2019 %t A116539 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}]]]; %t A116539 a[n_] := Sum[Sum[b[n, n, i]*(-1)^(k-i)*Binomial[k, i], {i, 0, k}], {k, 0, n}]; %t A116539 a /@ Range[0, 23] (* _Jean-François Alcover_, Feb 25 2020, after _Alois P. Heinz_ *) %Y A116539 Binary matrices with distinct rows and columns, various versions: A059202, A088309, A088310, A088616, A089673, A089674, A093466, A094000, A094223, A116532, A116539, A181230, A259763 %Y A116539 Cf. A049311, A058891, A101370, A255906, A283877, A306021, A319190. %Y A116539 Row sums of A326914 and of A326962. %K A116539 nonn %O A116539 0,3 %A A116539 _Vladeta Jovovic_, Mar 27 2006 %E A116539 a(0)=1 prepended and more terms added by _Alois P. Heinz_, Sep 13 2019