id:A112975 - OEIS Search Results

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Lexicographically smallest permutation of the natural numbers such that each term has a common divisor with at least two earlier terms, a(n)=n for n<4.

+0
6

1, 2, 3, 6, 4, 8, 9, 10, 12, 14, 15, 5, 16, 18, 20, 21, 7, 22, 24, 25, 26, 27, 28, 30, 32, 33, 11, 34, 35, 36, 38, 39, 13, 40, 42, 44, 45, 46, 48, 49, 50, 51, 17, 52, 54, 55, 56, 57, 19, 58, 60, 62, 63, 64, 65, 66, 68, 69, 23, 70, 72, 74, 75, 76, 77, 78, 80, 81, 82, 84, 85, 86 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`inverse: A112978; A112977 = a(a(n));` `for n>3: n is prime iff a(n) < a(n-1); a(A112976(n))=A000040(n).`
	LINKS	`Index entries for sequences that are permutations of the natural numbers`
	CROSSREFS	`Cf. A089088.` `Sequence in context: A154285 A036552 A132169 this_sequence A109890 A086537 A127562` `Adjacent sequences: A112972 A112973 A112974 this_sequence A112976 A112977 A112978`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 08 2005`

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Last modified December 15 00:47 EST 2009. Contains 170825 sequences.

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