A107058 a(n) = smallest number m>0 such that prime(n)*prime(n+1)-m is a prime.

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

Comments

a(n) is even for n > 1. - Seiichi Manyama, Mar 17 2025

Links

Seiichi Manyama, Table of n, a(n) for n = 1..10000

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.

Cf. A074928, A107019, A107057, A107059, A106172.

Sequence in context: A021413 A082855 A260588 * A332336 A101449 A221564

Adjacent sequences: A107055 A107056 A107057 * A107059 A107060 A107061

Keyword

nonn

Author

Zak Seidov, May 10 2005

Status

approved