A128548 Primes p such that p*q-p-q and p*q+p+q are prime where q=nextprime(p).

3, 5, 13, 43, 89, 163, 479, 643, 683, 773, 811, 953, 1109, 1399, 1471, 2213, 2741, 3253, 4583, 5153, 5923, 6427, 7649, 9059, 10151, 10531, 12301, 12373, 13553, 13903, 13921, 14723, 14869, 14929, 16183, 17123, 17681, 21149, 21377, 21569, 21587

Offset

1,1

Comments

Intersection of A126148 and A128546.

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Example

3*5-3-5=7 and 3*5+3+5=23 are prime, 5*7-5-23=7 and 5*7+5+7=47 are primes.

Prog

(PARI) isok(p) = isprime(p) && (q = nextprime(p+1)) && isprime(p*q-p-q) && isprime(p*q+p+q); \\ Michel Marcus, Oct 11 2013

Crossrefs

Cf. A096342, A126148, A128547.

Sequence in context: A178432 A236068 A057188 * A321358 A113606 A209002

Adjacent sequences: A128545 A128546 A128547 * A128549 A128550 A128551

Keyword

nonn

Author

Zak Seidov, Mar 10 2007

Status

approved