

A248872


Numbers n such that n^n + n! + 1 is prime.


0




OFFSET

1,2


COMMENTS

These primes are of the form: A000312(n) + A000142(n) + 1.
Note that 28 and 496 are perfect numbers (see A000396).
a(6) > 1500.


LINKS

Table of n, a(n) for n=1..5.


EXAMPLE

For n = 1, 1^1 + 1! + 1 = 3, which is prime.
For n = 2, 2^2 + 2! + 1 = 4 + 2 + 1 = 7, which is prime.
For n = 4, 4^4 + 4! + 1 = 281, which is prime.


MATHEMATICA

Select[Range[1500], PrimeQ[#^# + #! + 1]&]


PROG

(PARI) for(n=1, 10^3, if(ispseudoprime(n^n+n!+1), print1(n, ", "))) \\ Derek Orr, Mar 06 2015


CROSSREFS

Cf. A000312 (n^n), A000142(n!).
Sequence in context: A062792 A102692 A292184 * A329102 A126580 A329063
Adjacent sequences: A248869 A248870 A248871 * A248873 A248874 A248875


KEYWORD

nonn,more,hard


AUTHOR

Waldemar Puszkarz, Mar 04 2015


STATUS

approved



