OFFSET
1,2
PROG
(PARI) a(n) = { my(m=0, v = prime(n)*prime(n+1)); while (! isprime(v-m), m++; ); return (m); } \\ Michel Marcus, Apr 19 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, May 10 2005
STATUS
approved