OFFSET
1,1
PROG
(PARI) isok(n) = (n % 4 == 1) && isprime(2*n-1) \\ Michel Marcus, Jul 16 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Marco Matosic, Feb 17 2011
EXTENSIONS
More terms from Michel Marcus, Jul 16 2013
STATUS
approved