id:A157484 - OEIS Search Results

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Numbers n such that n-+1 are divisible by exactly 4 primes, counted with multiplicity.

+0
5

55, 89, 151, 197, 233, 249, 295, 307, 329, 341, 343, 349, 461, 489, 491, 569, 571, 665, 713, 739, 775, 851, 857, 859, 869, 871, 949, 1013, 1015, 1061, 1097, 1111, 1149 (list; graph; listen)

	OFFSET	`1,1`
	COMMENT	`54=2333;56=2227,...`
	MATHEMATICA	`q=4; lst={}; Do[If[Plus@@Last/@FactorInteger[n-1]==q&&Plus@@Last/@FactorInteger[n+1]==q, AppendTo[lst, n]], {n, 7!}]; lst`
	CROSSREFS	`Cf. A124936, A014612, A157483` `Sequence in context: A140377 A065912 A039533 this_sequence A027865 A143205 A111192` `Adjacent sequences: A157481 A157482 A157483 this_sequence A157485 A157486 A157487`
	KEYWORD	`nonn`
	AUTHOR	`Vladimir Orlovsky (4vladimir(AT)gmail.com), Mar 01 2009`

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.

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