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A105571 Numbers m such that m-2 and m+2 have 2 prime factors. 2
8, 12, 23, 24, 36, 37, 53, 60, 67, 84, 89, 93, 113, 117, 120, 121, 131, 143, 144, 157, 185, 203, 204, 207, 211, 215, 216, 217, 219, 251, 276, 289, 293, 297, 300, 301, 303, 307, 321, 325, 337, 360, 363, 379, 384, 393, 396, 405, 409, 413, 415, 449, 456, 471, 480 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

A001222(a(n)-2) = A001222(a(n)+2) = 2;

MATHEMATICA

q=2; lst={}; Do[If[Plus@@Last/@FactorInteger[n-q]==q&&Plus@@Last/@FactorInteger[n+q]==q, AppendTo[lst, n]], {n, 7!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Feb 01 2009]

CROSSREFS

Cf. A014574, A105572, A105573.

Sequence in context: A072843 A072902 A189322 * A141616 A088525 A054735

Adjacent sequences:  A105568 A105569 A105570 * A105572 A105573 A105574

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Apr 14 2005

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Last modified February 14 15:29 EST 2012. Contains 205631 sequences.