OFFSET
1,1
COMMENTS
All those p appear in A144562. [Proof: since 2p+3 is odd and not prime, it can be written as a product of two odd numbers, 2p+3=(2k+1)*(2s+1), therefore p=2ks+k+s-1. - R. J. Mathar, Aug 06 2009]
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
FORMULA
EXAMPLE
3 is in the sequence because 2*3+3=9 is composite; 23 is in the sequence because 2*23+3=49 is composite.
MATHEMATICA
Select[Prime[Range[200]], !PrimeQ[2#+3]&] (* Harvey P. Dale, Feb 02 2012 *)
PROG
(Magma) [p: p in PrimesUpTo(700) | not IsPrime(2*p+3)]; // Vincenzo Librandi, Apr 08 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Aug 04 2009
EXTENSIONS
Entries checked - R. J. Mathar, Aug 06 2009
STATUS
approved