A164622 Primes p such that p*floor(p/2) - 4 and p*floor(p/2) + 4 are prime numbers.

151, 463, 571, 631, 643, 991, 1063, 1171, 1831, 2083, 2311, 4951, 5023, 6211, 6703, 6763, 7723, 7951, 9043, 11383, 12163, 12391, 13183, 14851, 15031, 17431, 19231, 19543, 20143, 22051, 23143, 25951, 26371, 27283, 28351, 29131, 30643, 32803

Offset

1,1

Comments

151*75-4=11321 (prime), 151*75+4=11329 (prime), ..

Links

Table of n, a(n) for n=1..38.

Mathematica

lst={}; Do[p=Prime[n]; If[PrimeQ[p*Floor[p/2]-4]&&PrimeQ[p*Floor[p/2]+4], AppendTo[lst, p]], {n, 8!}]; lst

Crossrefs

Subsequence of A068229. Cf. A008846, A020882, A068229, A086519, A158708, A164620, A164621

Sequence in context: A002226 A142361 A142506 * A176138 A139640 A334836

Adjacent sequences: A164619 A164620 A164621 * A164623 A164624 A164625

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Aug 17 2009

Extensions

Edited by Charles R Greathouse IV, Nov 02 2009

Status

approved