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Numbers n such that n^(n+2) + (n+1)^(n+3) is prime.
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%I #11 Nov 14 2019 19:56:53

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

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

%C 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.

%C Results were computed using the PrimeFormGW (PFGW) primality-testing program. - _Hugo Pfoertner_, Nov 14 2019

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

%o (PARI) is(n)=isprime(n^(n+2)+(n+1)^(n+3)) \\ _Charles R Greathouse IV_, Jun 13 2017

%K nonn,more,hard

%O 1,2

%A _Jason Earls_, Jul 10 2004