id:A112927 - OEIS Search Results

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a(n) is the least prime such that the multiplicative order of 2 mod a(n) equals n, or a(n)=1 if no such prime exists.

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1, 3, 7, 5, 31, 1, 127, 17, 73, 11, 23, 13, 8191, 43, 151, 257, 131071, 19, 524287, 41, 337, 683, 47, 241, 601, 2731, 262657, 29, 233, 331, 2147483647, 65537, 599479, 43691, 71, 37, 223, 174763, 79, 61681 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`If a(n) differs from 1, then a(n) is the minimal prime divisor of A064078(n);` `a(n)=n+1 iff n+1 is prime from A001122; a(n)=2n+1 iff 2n+1 is prime from A115591.`
	CROSSREFS	`Cf. A002326 A064078 A001122 A115591.` `Sequence in context: A112071 A046561 A097406 this_sequence A064078 A048857 A005420` `Adjacent sequences: A112924 A112925 A112926 this_sequence A112928 A112929 A112930`
	KEYWORD	`nonn`
	AUTHOR	`Vladimir Shevelev (shevelev(AT)bgu.ac.il), Aug 25 2008`

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Last modified December 10 12:37 EST 2009. Contains 170569 sequences.

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