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A105974 (A001035(n) - 1)/2 where A001035 is the number of partially ordered sets ("posets") with n labeled elements. 0
0, 0, 1, 9, 109, 2115, 65011, 3064929, 215861689, 22255521255, 3305532624391, 698140838552949, 207432475527926749, 85925364190793529675, 49242162128564103516091, 38783585510220344176524969 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
COMMENTS
Conjectures: a(n) is (pre)periodic modulo m for all m, the lengths of the ending periods being given by 2*A000010(m) if m is a power of 2 and A000010(m) otherwise. A000010 is Euler's totient function.
LINKS
CROSSREFS
Sequence in context: A291815 A261502 A359731 * A053912 A053894 A053904
KEYWORD
nonn
AUTHOR
Gerald McGarvey, Apr 28 2005
STATUS
approved

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Last modified March 29 03:51 EDT 2024. Contains 371264 sequences. (Running on oeis4.)