A139064 Primes of the form (7+k!)/7.

5702401, 186810624001, 2988969984001, 2215887149047283712000001, 1476163995198020704238093048217600000001, 19811874077955690819705574245769915192271839538955347505831613562880000000000001

Offset: 1

Author

Artur Jasinski, Apr 07 2008

Keywords

• nonn

Comments

For numbers k for which (7+k!)/7 is prime see A139065.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..12

Crossrefs

Cf. A020458, A082672, A089085, A089130, A117141, A007749, A139056, A139057, A139058, A139059, A139060, A139061, A139062, A139063, A139065, A139066, A139154.

Programs

Mathematica

a = {}; Do[If[PrimeQ[(n! + 7)/7], AppendTo[a, (n! + 7)/7]], {n, 1, 50}]; a

PARI

for(k=7,1e3,if(ispseudoprime(t=k!/7+1),print1(t", "))) \\ Charles R Greathouse IV, Jul 15 2011

Formula

a(n) = A139154(A139065(n)). - Amiram Eldar, Oct 14 2024