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A175502 a(1) = 1. a(n) = the smallest integer not yet occurring such that each unordered pair {d(a(k)),d(a(k-1))} occurs only once at most, for 2<= k <= n, where d(m) = the number of divisors of m. 3
1, 2, 3, 4, 6, 5, 12, 8, 10, 16, 7, 24, 9, 18, 20, 30, 14, 36, 11, 48, 15, 60, 13, 64, 21, 120, 17, 144, 22, 180, 19, 192, 25, 49, 72, 28, 80, 40, 42, 81, 32, 100, 54, 84, 90, 112, 121, 168, 44, 240, 23, 360, 26, 320, 45, 252, 56, 210, 96, 196 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

This sequence seems likely to be a permutation of the positive integers. Is it?

LINKS

Ivan Neretin, Table of n, a(n) for n = 1..1000

CROSSREFS

Cf. A175500, A175503

Sequence in context: A075160 A119755 A206710 * A240809 A214322 A075527

Adjacent sequences:  A175499 A175500 A175501 * A175503 A175504 A175505

KEYWORD

nonn

AUTHOR

Leroy Quet, May 31 2010

EXTENSIONS

More terms from Sean A. Irvine, Jun 14 2011

STATUS

approved

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Last modified May 26 18:08 EDT 2020. Contains 334630 sequences. (Running on oeis4.)