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A181285 Primes of the form 5^n - 4. 1
3121, 78121, 30517578121, 710542735760100185871124267578121, 413590306276513837435704346034981426782906055450439453121 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..4.

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. A135535

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

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Last modified September 28 22:01 EDT 2020. Contains 337417 sequences. (Running on oeis4.)