A240503 Numbers k such that 5^k - 4^k - 3^k - 2^k - 1 is prime.

4, 8, 72, 396, 4428, 63152

Offset: 1

Author

Derek Orr, Apr 06 2014

Keywords

• nonn
• more

Comments

a(7) > 70000. - Giovanni Resta, Apr 09 2014

a(7) > 110000. - Michael S. Branicky, Jul 06 2024

Examples

			5^4-4^4-3^4-2^4-1 = 271 is prime. Thus, 4 is a term of this sequence.
		

Crossrefs

Cf. A000043, A240507.

Programs

PARI

for(n=1,7500,if(ispseudoprime(5^n-4^n-3^n-2^n-1),print(n)))

Extensions

a(6) from Giovanni Resta, Apr 09 2014