OFFSET
1,1
COMMENTS
Some primes have no unique representation (besides of symmetry in p,q!), e.g. 11 with (p,q)=(2,13) and (3,7).
LINKS
T. D. Noe, Table of n, a(n) for n=1..1000
EXAMPLE
31 is a member with p=3, q=17.
MATHEMATICA
mp[{p_, q_}]:=p*q-p-q; Take[Union[Select[mp/@Subsets[Prime[Range[100]], {2}], PrimeQ]], 60] (* Harvey P. Dale, Nov 27 2011 *)
PROG
(PARI) isA091305(p)=fordiv(p++, d, if(isprime(d+1)&isprime(p/d+1), return(isprime(p-1)))) \\ Charles R Greathouse IV, Feb 15 2011
CROSSREFS
KEYWORD
easy,nice,nonn
AUTHOR
Zak Seidov, Feb 21 2004
STATUS
approved