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A058793 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. 0
1, 6, 73, 2957, 431805 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

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

LINKS

Table of n, a(n) for n=1..5.

Formula

CROSSREFS

Cf. A050535, A050913, A058783-A058785.

Sequence in context: A135594 A168603 A244689 * A066171 A269647 A232330

Adjacent sequences:  A058790 A058791 A058792 * A058794 A058795 A058796

KEYWORD

more,nonn

AUTHOR

Vladeta Jovovic, Nov 30 2000

STATUS

approved

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Last modified January 18 16:27 EST 2020. Contains 331011 sequences. (Running on oeis4.)