A163624 Numbers n such that 120n+1 is prime.

2, 5, 10, 11, 15, 18, 19, 21, 25, 26, 28, 35, 37, 38, 40, 44, 46, 47, 49, 51, 53, 54, 57, 58, 61, 63, 64, 68, 71, 72, 73, 75, 77, 80, 81, 86, 93, 102, 105, 106, 107, 112, 114, 116, 119, 120, 126, 127, 128, 130, 138, 141, 142, 145, 148, 149, 151, 154, 159, 162, 164, 165

Offset: 1

Author

Zak Seidov, Aug 01 2009

Keywords

• nonn
• easy

Links

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

Crossrefs

Cf. A163623.

Programs

Magma

[n: n in [0..250]|IsPrime(120*n+1)]; // Vincenzo Librandi, Dec 13 2010

Mathematica

Select[Range[200], PrimeQ[120 # + 1] &] (* Harvey P. Dale, May 29 2013 *)

PARI

is(n)=isprime(120*n+1) \\ Charles R Greathouse IV, Feb 20 2017

Formula

a(n) = (A163623(n)-1)/120.