A181285 Primes of the form 5^k - 4.

3121, 78121, 30517578121, 710542735760100185871124267578121, 413590306276513837435704346034981426782906055450439453121

Offset

1,1

Links

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

Example

3121 = 5^5 - 4 is prime and therefore is in the sequence.

Maple

n:=1000: S:={}: for i from 1 to n do if type(5^i-4, prime)=true then S:=S union {5^i-4} end if od; S;

Mathematica

Select[5^Range[90]-4, PrimeQ] (* Harvey P. Dale, Aug 23 2013 *)

Crossrefs

Cf. A059613, A135535, A228028.

Sequence in context: A183850 A002433 A107535 * A133526 A250523 A251061

Adjacent sequences: A181282 A181283 A181284 * A181286 A181287 A181288

Keyword

nonn

Author

Jonathan D. B. Hodgson, Oct 12 2010

Status

approved