OFFSET
1,1
COMMENTS
In all terms except 3, r is odd. - Robert Israel, Jun 08 2018
LINKS
Robert Israel, Table of n, a(n) for n = 1..1736
MAPLE
N:= 10^30: # for all terms <= N
sort(select(isprime, [3, seq(seq(2^r*7^s-1, r=1..ilog2((N+1)/7^s), 2),
s=0..floor(log[7]((N+1)/2)))])); # Robert Israel, Jun 08 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Nov 04 2002
EXTENSIONS
Corrected and extended by Ray Chandler, Aug 02 2003
STATUS
approved