OFFSET
1,1
COMMENTS
a(6), if it exists, is greater than 5000. - Vaclav Kotesovec, Apr 01 2018
a(6), if it exists, is greater than 20000. - Michael S. Branicky, Sep 02 2024
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
KEYWORD
nonn,more,hard
AUTHOR
Seiichi Manyama, Apr 01 2018
EXTENSIONS
a(5) from Vaclav Kotesovec, Apr 01 2018
STATUS
approved