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A181806
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Positive integers with more highly composite divisors (A002182) than any smaller positive integer.
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7
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1, 2, 4, 12, 24, 48, 120, 240, 360, 720, 5040, 10080, 15120, 30240, 60480, 151200, 166320, 332640, 665280, 1663200, 1995840, 3326400, 8648640, 17297280, 21621600, 43243200, 86486400, 129729600, 259459200, 735134400
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OFFSET
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1,2
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COMMENTS
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Numbers n such that A181801(n) > A181801(m) for all m < n. Also, numbers n such that row n of triangles A181802 and A181803 is longer than any previous row in either triangle.
Not a subsequence of A002182. The smallest positive integer which has a record number of highly composite divisors, but which is not highly composite itself, is 30240.
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LINKS
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Charles R Greathouse IV, Table of n, a(n) for n = 1..153
A. Flammenkamp, List of the first 1200 highly composite numbers
Eric Weisstein's World of Mathematics, Highly composite number
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EXAMPLE
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12 has five divisors (namely, 1, 2, 4, 6 and 12) that are members of A002182. No positive integer smaller than 12 has more than three members of A002182 among its divisors; hence, 12 is a member of the sequence.
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CROSSREFS
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A181807(n) = number of highly composite divisors of a(n) (i.e., A181801(a(n)).
Subsequence of A025487, A181804. Numbers A181804(n) such that A181805(n) increases to a record.
Includes all members of A136253.
Sequence in context: A079352 A089888 A181809 * A133411 A201078 A004645
Adjacent sequences: A181803 A181804 A181805 * A181807 A181808 A181809
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KEYWORD
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nonn,changed
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AUTHOR
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Matthew Vandermast, Nov 27 2010
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EXTENSIONS
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a(20)-a(30) from Charles R Greathouse IV, Jan 14 2011
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STATUS
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approved
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