A217080 Numbers n such that (n^53-1)/(n-1) is prime.

24, 45, 60, 165, 235, 272, 285, 298, 307, 381, 416, 429, 623, 799, 858, 924, 929, 936, 1034, 1067, 1076, 1130, 1223, 1243, 1327, 1488, 1592, 1594, 1659, 1673, 1676, 1678, 1762, 1873, 1917, 1928, 1997, 2110, 2117, 2141, 2166, 2231, 2243, 2293, 2338, 2380, 2420

Offset: 1

Author

Tim Johannes Ohrtmann, Sep 26 2012

Keywords

• nonn

Links

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

Crossrefs

Cf. A002384, A049409, A100330, A162862, A217070-A217089.

Programs

Magma

[n: n in [2..2450] |IsPrime((n^53 - 1) div (n - 1))]; // Vincenzo Librandi, Sep 28 2012

Mathematica

Select[Range[2, 2500], PrimeQ[(#^53 - 1)/(# - 1)] &] (* T. D. Noe, Sep 26 2012 *)

PARI

is(n)=isprime((n^53-1)/(n-1)) \\ Charles R Greathouse IV, Feb 17 2017

Extensions

More terms from T. D. Noe, Sep 26 2012