|
| |
|
|
A057187
|
|
Numbers n such that (21^n+1)/22 is a prime.
|
|
14
|
|
|
|
3, 5, 7, 13, 37, 347, 17597, 59183, 80761, 210599, 394579
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,1
|
|
|
COMMENTS
|
Some of the larger terms correspond to probable primes.
|
|
|
LINKS
|
Table of n, a(n) for n=1..11.
H. Dubner and T. Granlund, Primes of the Form (b^n+1)/(b+1), J. Integer Sequences, 3 (2000), #P00.2.7.
H. Lifchitz, Mersenne and Fermat primes field
Paul Bourdelais, A Generalized Repunit Conjecture [From Paul Bourdelais, Mar 24 2010]
|
|
|
PROG
|
(Prime95) PRP=1, 21, 394579, 1, 0, 0, "22"
|
|
|
CROSSREFS
|
Sequence in context: A047933 A075557 A244452 * A163080 A141414 A236464
Adjacent sequences: A057184 A057185 A057186 * A057188 A057189 A057190
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
N. J. A. Sloane, Sep 15 2000
|
|
|
EXTENSIONS
|
a(7) from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008
a(8) corresponds to a probable prime discovered by Paul Bourdelais, Mar 22 2010
a(9) corresponds to a probable prime discovered by Paul Bourdelais, Mar 24 2010
a(10) corresponds to a probable prime discovered by Paul Bourdelais, Aug 30 2013
a(11) corresponds to a probable prime discovered by Paul Bourdelais, Oct 23 2018
|
|
|
STATUS
|
approved
|
| |
|
|
