A072026 - OEIS

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A072026

Swap twin prime pairs >(3,5) in prime factorization of n.

1, 2, 3, 4, 7, 6, 5, 8, 9, 14, 13, 12, 11, 10, 21, 16, 19, 18, 17, 28, 15, 26, 23, 24, 49, 22, 27, 20, 31, 42, 29, 32, 39, 38, 35, 36, 37, 34, 33, 56, 43, 30, 41, 52, 63, 46, 47, 48, 25, 98, 57, 44, 53, 54, 91, 40, 51, 62, 61, 84, 59, 58, 45, 64, 77, 78 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`1,2`
	COMMENTS	`a(a(n))=n, a self-inverse permutation of natural numbers;` `a(n)=n for single primes (A007510) and products of twin prime pairs (A037074).`
	LINKS	`Table of n, a(n) for n=1..66.` `Index entries for sequences that are permutations of the natural numbers`
	FORMULA	`Multiplicative with a(p) = (if p<=3 then p else (if p+2 is prime then p+2 else (if p-2 is prime then p-2 else p))), p prime.`
	EXAMPLE	`a(143)=a(1113)=a(11)a(13)=1311=143; a(77)=a(711)=a(7)a(11)=513=65.`
	CROSSREFS	`Cf. A072027, A001359, A006512, A072028, A072029, A061898, A064505.` `Sequence in context: A331275 A072028 A269377 * A332213 A235199 A270426` `Adjacent sequences: A072023 A072024 A072025 * A072027 A072028 A072029`
	KEYWORD	`nonn,mult`
	AUTHOR	`Reinhard Zumkeller, Jun 07 2002`
	STATUS	`approved`

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Last modified March 9 05:13 EST 2021. Contains 341962 sequences. (Running on oeis4.)