id:A092058 - OEIS Search Results

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A092058

Numbers n such that 2*prime(n)^2-1 is prime.

+0
4

1, 2, 4, 5, 6, 7, 13, 14, 17, 21, 29, 30, 31, 33, 37, 41, 42, 45, 46, 47, 54, 56, 59, 62, 64, 71, 73, 75, 80, 81, 84, 93, 103, 105, 106, 113, 114, 120, 126, 131, 132, 134, 139, 141, 144, 145, 146, 148, 159, 160, 169, 175, 179, 183, 185, 186, 188, 192, 212, 217, 220 (list; graph; listen)

	OFFSET	`1,2`
	EXAMPLE	`2prime(1)^2-1 = 7 is prime so a(1)=1` `2prime(2)^2-1 = 17 is prime so a(2)=2` `2prime(3)^2-1 = 97 is not prime` `2prime(4)^2-1 = 241 is prime so a(3)=4`
	PROGRAM	`(PARI) for (i=1, 300, if(isprime(2*prime(i)^2-1), print1(i, ", ")))`
	CROSSREFS	`Cf. A092057.` `Sequence in context: A139448 A070116 A039057 this_sequence A134532 A133398 A138836` `Adjacent sequences: A092055 A092056 A092057 this_sequence A092059 A092060 A092061`
	KEYWORD	`easy,nonn`
	AUTHOR	`mohammed Bouayoun (mohammed.bouayoun(AT)sanef.com), Feb 19 2004`

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Last modified November 30 22:12 EST 2008. Contains 150989 sequences.

AT&T Labs Research