A176792 Primes in A014293.

7, 79, 1021, 3486784393, 155568095557812211, 6176733962839469999999999999999999999999999971

Offset

1,1

Comments

Prime solutions to the classical "Monkey and Coconut Problem." Primes of the form n^(n+1)-n+1. A014293(n) is prime for n = 2, 3, 4, 9, 14, 30, 62, 75, 156, ..., .

The next term has 113 digits.

Links

Table of n, a(n) for n=1..6.

Formula

{n^(n+1)-n+1 : n nonnegative integer and n^(n+1)-n+1 in A000040} == A014293 INTERSECTION A000040.

Example

A014293(0) = A014293(1) = 1 is nonprime, so 1 is not in this sequence.
A014293(2) = 7 is prime, so 7 is in this sequence.
A014293(3) = 79 is prime, so 79 is in this sequence.
A014293(4) = 1021 is prime, so 1021 is in this sequence.
A014293(5) = 15621 = 3 * 41 * 127 is nonprime, so 15621 is not in this sequence.

Mathematica

Select[#^(# + 1) - # + 1 & /@ Range@ 75, PrimeQ]

Prog

(Magma) [ a: n in [0..250] | IsPrime(a) where a is (n^(n+1)-n+1)] // Vincenzo Librandi, Jan 30 2011

Crossrefs

Cf. A000040.

Sequence in context: A198973 A127859 A014293 * A186377 A112700 A365039

Adjacent sequences: A176789 A176790 A176791 * A176793 A176794 A176795

Keyword

nonn

Author

Jonathan Vos Post, Dec 07 2010

Status

approved