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Number of covers of an unlabeled n-set such that every point of the set is covered by exactly 6 subsets of the cover and that intersection of every 6 subsets of the cover contains at most one point.
1

%I #10 Jan 29 2020 20:34:04

%S 1,6,73,2957,431805,193413963,198914729182,389238347659505,

%T 1292594846197639190,6753309741099683530616

%N Number of covers of an unlabeled n-set such that every point of the set is covered by exactly 6 subsets of the cover and that intersection of every 6 subsets of the cover contains at most one point.

%C Cover may include multiple occurrences of a subset. Also n-rowed binary matrices with distinct rows and all row sums 6.

%H Vladeta Jovovic, <a href="/A058790/a058790.pdf">Formula</a>

%Y Row n=6 of A331508.

%Y Cf. A050535, A050913, A058783, A058784, A058785.

%K more,nonn

%O 1,2

%A _Vladeta Jovovic_, Nov 30 2000

%E a(6)-a(10) from _Andrew Howroyd_, Jan 29 2020