OFFSET
1,1
COMMENTS
All terms are multiples of 3, a(n) = 3*A125272(n). - Zak Seidov, May 06 2013
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
9 = 3^2 is a term since it is a semiprime, and both 9 - 2 = 7 and 9 + 2 = 11 are primes.
MATHEMATICA
Reap[Do[p=Prime[i]; If[PrimeQ[p+4]&&Total[Last/@FactorInteger[p+2]]==2, Sow[p+2]], {i, 2*10^3}]][[2, 1]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Nov 24 2006
STATUS
approved