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%I #20 Feb 28 2023 21:09:17
%S 1,7,62,664,8609,127415,2004975,31500927,474504448,6708348262,
%T 88249739792,1078567590128,12269901302433,130370516668917,
%U 1298891291366245,12182760243381355,107979270564656625,907568508195185203,7256984238345563764,55365443728411530716,404091280028746802188
%N Number of 7-covers of an unlabeled n-set.
%C Number of 7 X n binary matrices with at least one 1 in every column up to row and column permutations. - _Andrew Howroyd_, Feb 28 2023
%H Andrew Howroyd, <a href="/A055066/b055066.txt">Table of n, a(n) for n = 0..1000</a>
%H Vladeta Jovovic, <a href="/A005748/a005748.pdf">Binary matrices up to row and column permutations</a>
%o (PARI) Vec(G(7, x)*(1-x) + O(x^40)) \\ G defined in A028657. - _Andrew Howroyd_, Feb 28 2023
%Y Column 7 of A055080.
%Y Cf. A005748, A002620, A005783, A005784, A005785, A005786.
%K nonn
%O 0,2
%A _Vladeta Jovovic_, Jun 12 2000
%E a(0)=1 prepended by _Alois P. Heinz_, Aug 08 2022
%E Terms a(17) and beyond from _Andrew Howroyd_, Feb 28 2023
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