A190423 Primes p such that the least k with p+k and p+2k both prime sets a new record.

3, 5, 13, 37, 73, 179, 503, 757, 1223, 1249, 1831, 2003, 4051, 6991, 17483, 18353, 18457, 22567, 26993, 47129, 88327, 131357, 136753, 215753, 344293, 499673, 2499143, 3345877, 3984391, 4065461, 5062649, 5418421, 7933109, 8865331, 11339287, 12464401, 18606089

Offset

1,1

Comments

This sequence is conjectured to be infinite, but this is expected to be roughly as hard as the twin prime conjecture.

Links

Donovan Johnson, Table of n, a(n) for n = 1..60

Prog

(PARI) print1(r=3); forprime(p=5, 4e9, forstep(k=6, 9e9, 6, if(isprime(p+k) && isprime(p+2*k), if(k>r, r=k; print1(", "p)); break)))

Crossrefs

Cf. A120627, A190424.

Sequence in context: A005383 A306826 A175257 * A278024 A198636 A172023

Adjacent sequences: A190420 A190421 A190422 * A190424 A190425 A190426

Keyword

nonn

Author

Charles R Greathouse IV, May 10 2011

Status

approved