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A115093 Primes of the form p*q-2, where p and q are distinct primes. 2
13, 19, 31, 37, 53, 67, 83, 89, 109, 113, 127, 131, 139, 157, 181, 199, 211, 233, 251, 257, 263, 293, 307, 317, 337, 353, 379, 389, 401, 409, 443, 449, 467, 479, 487, 491, 499, 503, 509, 541, 557, 563, 571, 577, 587, 631, 647, 653, 677, 683, 701, 719, 743 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

This sequence is a subset of A063637, which is the union of this sequence and A049002.

LINKS

Table of n, a(n) for n=1..53.

MATHEMATICA

SemiPrimeQ[n_] := (n>1) && (2==Plus@@(Transpose[FactorInteger[n]][[2]])); Select[Prime[Range[150]], SemiPrimeQ[ #+2] && !IntegerQ[Sqrt[ #+2]]&]

CROSSREFS

Cf. A049002 (primes of the form p^2-2, where p is prime), A063637 (primes of the form p*q-2 where p and q are primes).

Sequence in context: A102764 A164318 A092738 * A158195 A040092 A079130

Adjacent sequences:  A115090 A115091 A115092 * A115094 A115095 A115096

KEYWORD

nonn

AUTHOR

T. D. Noe, Mar 01 2006

STATUS

approved

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Last modified May 25 01:09 EDT 2013. Contains 225631 sequences.