A181681 Primes of the form k^(k+1)+(k-1)^k.

89, 16649, 6044737, 3238428376721

Offset

1,1

Comments

The next term of the sequence is a(5) = 393^394+392^393 = 15526396580196065...8500849703002799761, which has 1023 decimal digits and is too large to include here.

Links

Table of n, a(n) for n=1..4.

Example

For k=5, 16649 is in the sequence because 5^6+4^5=16649 is prime.

Mathematica

lst={}; Do[m=n+1; q=n^m+ (n-1)^n; If[PrimeQ[q], AppendTo[lst, q]], {n, 0, 400}]; lst

Prog

(PARI) A181681() = {for(n=1, 400, if(isprime(p=n^(n+1)+(n-1)^n), print1(p, ", "))); }

Crossrefs

Sequence in context: A086695 A056568 A174758 * A167398 A023330 A059766

Adjacent sequences: A181678 A181679 A181680 * A181682 A181683 A181684

Keyword

nonn

Author

Michel Lagneau, Nov 17 2010

Status

approved