login
A107058
a(n) = smallest number m>0 such that prime(n)*prime(n+1)-m is a prime.
3
1, 2, 4, 4, 4, 10, 6, 4, 6, 12, 18, 6, 4, 4, 14, 6, 6, 8, 6, 4, 18, 4, 18, 4, 6, 4, 18, 6, 16, 4, 4, 8, 6, 4, 16, 18, 2, 10, 12, 18, 18, 22, 6, 10, 4, 6, 2, 22, 6, 4, 6, 6, 34, 8, 2, 18, 6, 26, 24, 30, 6, 12, 6, 16, 30, 10, 8, 6, 22, 6, 8, 4, 2, 8, 18, 26, 10, 4, 12, 30, 10, 12, 4, 24, 6, 6, 6
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
Cf. A107059: records in A107058; A106172: positions of records in A107058. Cf. A074928: a(n)>0 such that p(n)*p(n+1)+a(n) is a smallest prime.
Sequence in context: A021413 A082855 A260588 * A332336 A101449 A221564
KEYWORD
nonn
AUTHOR
Zak Seidov, May 10 2005
STATUS
approved