A168447 Primes p such that floor(p/6) is also prime.

13, 17, 19, 23, 31, 43, 47, 67, 71, 79, 83, 103, 107, 139, 179, 191, 223, 227, 251, 263, 283, 359, 367, 431, 439, 443, 479, 499, 503, 587, 607, 619, 643, 647, 659, 683, 787, 823, 827, 839, 907, 911, 947, 983, 1039, 1087, 1091, 1151, 1163, 1187, 1367, 1399

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Formula

a(n) >> n log^2 n. - Charles R Greathouse IV, Feb 23 2017

Mathematica

Select[Prime[Range[6! ]], PrimeQ[Floor[ #/6]]&]

Prog

(Magma) [p: p in PrimesUpTo(1400) | IsPrime(Floor(p/6))]; // Vincenzo Librandi, Apr 16 2013
(PARI) is(n)=isprime(n) && isprime(n\6) \\ Charles R Greathouse IV, Feb 23 2017

Crossrefs

Cf. A075519, A168446.

Sequence in context: A156666 A331487 A286042 * A191059 A165681 A214033

Adjacent sequences: A168444 A168445 A168446 * A168448 A168449 A168450

Keyword

nonn,easy

Author

Vladimir Joseph Stephan Orlovsky, Nov 25 2009

Extensions

Definition corrected by R. J. Mathar, Dec 06 2009

Status

approved