id:A139048 - OEIS Search Results

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a(n) = the number of primes p, p <= the nth prime, where (p + (1/p)product{k=1 to n} p(k)) is prime, where p(k) is the kth prime.

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1, 2, 3, 4, 3, 4, 3, 2, 2, 5, 2, 4, 2, 2, 6, 2, 3, 4, 4, 3, 5, 1, 3, 3, 3, 2, 3, 3, 6, 2, 1, 0, 0, 1, 2, 6, 2, 3, 1, 7, 3, 1, 1, 2, 0, 1, 4, 4, 2, 4, 4, 0, 3, 3, 4, 1, 2, 4, 2, 2, 1, 2, 2, 2, 1, 3, 2, 1, 4, 3, 2, 3, 2, 3, 3, 4, 5, 2, 2, 5, 4, 2, 2, 1, 2, 2, 1, 5, 0, 2, 1, 2, 4, 2, 4, 4, 1, 5, 1, 1, 1, 3, 2, 1, 1 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`Sequence's terms were calculated by Jacques Tramu.` `Variant of A083021. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 03 2008]`
	LINKS	`Leroy Quet, Home Page (listed in lieu of email address)`
	EXAMPLE	`For n = 5: 2 + 35711 = 1157 = 1389; 3 + 25711 = 773 = prime; 5 + 23711 = 467 = prime; 7 + 23511 = 337 = prime; 11 + 2357 = 221 = 13*17. So a(5) = 3.`
	CROSSREFS	`Cf. A002110.` `Sequence in context: A079086 A017839 A106826 this_sequence A158515 A123709 A165482` `Adjacent sequences: A139045 A139046 A139047 this_sequence A139049 A139050 A139051`
	KEYWORD	`nonn`
	AUTHOR	`Leroy Quet Jun 01 2008`

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Last modified November 27 14:50 EST 2009. Contains 167570 sequences.

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