OFFSET
1,5
COMMENTS
If a(n) = 0, then 2^prime(n) - 1 is a prime greater than 3. - Alonso del Arte, May 09 2014
For n > 1, 2^prime(n) - 1 is prime if and only if a(n) = 0. - Thomas Ordowski, Aug 12 2018
LINKS
Dennis Martin, Table of n, a(n) for n = 1..100
Eric Weisstein's World of Mathematics, Lucas-Lehmer Test
FORMULA
First, s(0) = 4, s(i) = s(i - 1)^2 - 2. Then, a(n) = s(prime(n) - 2) mod 2^prime(n) - 1. - Alonso del Arte, May 09 2014
EXAMPLE
The first term is 1 since 4 mod 3 = 1. - Zvi Mendlowitz (zvi113(AT)zahav.net.il), May 10 2006
MATHEMATICA
(* First run the program for A003010 to define seqLucasLehmer *) Table[Mod[seqLucasLehmer[Prime[n] - 2], 2^Prime[n] - 1], {n, 20}] (* Alonso del Arte, May 09 2014 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Jun 08 2004
STATUS
approved