A139059 Primes of the form (5+k!)/5.

1009, 72577, 7983361, 17435658241, 24329020081766401, 5170403347776995328001, 23924444173096038912392632299131543012876746752000000001

Offset: 1

Author

Artur Jasinski, Apr 07 2008

Keywords

• nonn

Comments

For numbers k for which (5+k!)/5 is prime see A139058.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10

Crossrefs

Cf. A082672, A089085, A089130, A117141, A007749, A139056-A139066, A139068, A137390, A139070-A139075, A139152.

Programs

Magma

[ a: n in [1..50] | IsPrime(a) and b mod 5 eq 0 where a is b div 5 where b is Factorial(n)+5 ];

Mathematica

a = {}; Do[If[PrimeQ[(n! + 5)/5], AppendTo[a, (n! + 5)/5]], {n, 1, 50}]; a
Select[(5+Range[50]!)/5,PrimeQ] (* Harvey P. Dale, Dec 04 2020 *)

PARI

for(k=5,1e3,if(ispseudoprime(t=(5+k!)/5),print1(t", "))) \\ Charles R Greathouse IV, Jul 15 2011

Formula

a(n) = A139152(A139058(n)). - Amiram Eldar, Oct 14 2024