A095829 - OEIS

A095829

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

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

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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.

Results were computed using the PrimeFormGW (PFGW) primality-testing program. - Hugo Pfoertner, Nov 14 2019

LINKS

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

KEYWORD

nonn,more,hard

AUTHOR

Jason Earls, Jul 10 2004

STATUS

approved