A100840 Primes of the form k^k + 4.

5, 31, 823547, 17343773367030267519903781288812032158308062539012091953077767198995511

Offset

1,1

Comments

From Daniel Starodubtsev, Aug 03 2019: (Start)

a(5) = 2569^2569 + 4 (8760 digits long).

a(6) > 15000^15000 + 4. (End)

Links

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

Mathematica

lst={}; Do[p=n^n+4; If[PrimeQ[p], AppendTo[lst, p]], {n, 5!}]; lst (* Vladimir Joseph Stephan Orlovsky, Nov 01 2009 *)
Select[Table[n^n+4, {n, 50}], PrimeQ] (* Harvey P. Dale, Oct 09 2020 *)

Prog

(PARI) f1(n) = for(x=1, n, y=x^x+4; if(ispseudoprime(y), print1(y", ")))

Crossrefs

Cf. A100837 (corresponding k).

Sequence in context: A278574 A062631 A156027 * A265159 A247549 A140154

Adjacent sequences: A100837 A100838 A100839 * A100841 A100842 A100843

Keyword

hard,nonn

Author

Cino Hilliard, Jan 07 2005

Status

approved