

A302088


Numbers k such that 5*k^k + 4 is prime.


2




OFFSET

1,1


COMMENTS

Next term, if it exists, is greater than 5000.


LINKS

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


MATHEMATICA

Select[Range[1, 1000], PrimeQ[5*#^# + 4] &] (* Vaclav Kotesovec, Apr 01 2018 *)


PROG

(PARI) for(n=0, 500, if(isprime(5*n^n+4), print1(n", ")))
(PARI) lista(nn) = forstep(n=1, nn, 2, if(ispseudoprime(5*n^n+4), print1(n, ", "))); \\ Altug Alkan, Apr 01 2018


CROSSREFS

Numbers k such that b*k^k + b  1 is prime: A110932 (b=2), A160360 (b=3), A301520 (b=4), this sequence (b=5), A302090 (b=6).
Cf. A302089.
Sequence in context: A121622 A188983 A083519 * A211414 A173706 A332359
Adjacent sequences: A302085 A302086 A302087 * A302089 A302090 A302091


KEYWORD

nonn,more,hard


AUTHOR

Seiichi Manyama, Apr 01 2018


EXTENSIONS

a(5) from Vaclav Kotesovec, Apr 01 2018


STATUS

approved



