id:A117328 - OEIS Search Results

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Primes p such that p+/-4 are semiprimes.

+0
3

29, 53, 61, 73, 89, 137, 173, 181, 263, 331, 449, 523, 541, 547, 569, 577, 587, 593, 683, 691, 727, 811, 839, 947, 1051, 1063, 1153, 1163, 1223, 1259, 1289, 1367, 1531, 1559, 1627, 1637, 1847, 1861, 1933, 1973, 1987, 2099, 2153, 2161, 2213, 2267, 2287, 2311 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`Cf. A063643 Primes p such that p+/-2 are semiprimes.`
	EXAMPLE	`29-4=25=55 (semiprime). 29+4=33=311 (semiprime).`
	MATHEMATICA	`fQ[n_] := Plus @@ Last /@ FactorInteger@n == 2; Select[ Prime@ Range[3, 345], fQ[ # - 4] && fQ[ # + 4] &] (from Robert G. Wilson v (rgwv(at)rgwv.com), May 01 2006)`
	CROSSREFS	`Cf. A063643.` `Sequence in context: A108258 A042947 A134555 this_sequence A105406 A124284 A054822` `Adjacent sequences: A117325 A117326 A117327 this_sequence A117329 A117330 A117331`
	KEYWORD	`nonn`
	AUTHOR	`Zak Seidov (zakseidov(AT)yahoo.com), Mar 08 2006`

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Last modified August 29 17:54 EDT 2008. Contains 143238 sequences.

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