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A059201
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Number of T_0-covers of a labeled n-set.
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4
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1, 1, 4, 96, 31692, 2147001636, 9223371991763269704, 170141183460469231473432887375376674952, 57896044618658097711785492504343953920509909728243389682424010192567186540224
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OFFSET
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0,3
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COMMENTS
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A cover of a set is a T_0-cover if for every two distinct points of the set there exists a member (block) of the cover containing one but not the other point.
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LINKS
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Table of n, a(n) for n=0..8.
Vladeta Jovovic, T_0-covers of a labeled 3-set
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FORMULA
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a(n)=Sum_{i=0..n+1} stirling1(n+1, i)*2^(2^(i-1)-1).
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CROSSREFS
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Cf. A003465, row sums of A059202, A059203, A059084-A059089.
Sequence in context: A146514 A181335 A098695 * A027638 A041275 A024384
Adjacent sequences: A059198 A059199 A059200 * A059202 A059203 A059204
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KEYWORD
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easy,nonn
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AUTHOR
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Vladeta Jovovic, Goran Kilibarda (vladeta(AT)eunet.rs), Jan 16 2001
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STATUS
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approved
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