A168446 Primes p such that floor(p/5) is also prime.

11, 13, 17, 19, 29, 37, 59, 67, 89, 97, 149, 157, 239, 269, 307, 337, 359, 367, 397, 419, 449, 487, 509, 547, 569, 659, 757, 787, 839, 907, 967, 997, 1117, 1259, 1289, 1319, 1409, 1559, 1567, 1657, 1747, 1867, 1949, 1987, 2099, 2287, 2309, 2339, 2399, 2437, 2459

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Nov 25 2009

Keywords

• nonn
• easy

Links

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

Crossrefs

Cf. A075519, A168447.

Programs

Magma

[p: p in PrimesUpTo(2500) | IsPrime(Floor(p/5))]; // Vincenzo Librandi, Apr 16 2013

Mathematica

Select[Prime[Range[6! ]],PrimeQ[Floor[ #/5]]&]

Extensions

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