A095829 Numbers k such that k^(k+2) + (k+1)^(k+3) is prime.

1, 3, 5, 6, 9, 21, 24, 35, 84, 396, 1585

Offset

1,2

Comments

a(1) through a(9) have been proved to be prime. 396^398 + 397^399 is Fermat and Lucas PRP. 1585^1587 + 1586^1588 is 3-PRP. No more terms up to 2150.

No more terms up to 20000. - Michael S. Branicky, Nov 23 2024

Links

Table of n, a(n) for n=1..11.

Example

a(5)=9 because 9^11 + 10^12 = 1031381059609 is prime.

Prog

(PARI) is(n)=isprime(n^(n+2)+(n+1)^(n+3)) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Sequence in context: A309140 A102606 A102372 * A054871 A248644 A242197

Adjacent sequences: A095826 A095827 A095828 * A095830 A095831 A095832

Keyword

nonn,more,hard

Author

Jason Earls, Jul 10 2004

Status

approved