|
| |
|
|
A103022
|
|
Numbers n such that 5*10^n + 8*R_n - 7 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
|
|
1
|
|
|
|
3, 5, 6, 21, 309, 816, 858, 1115, 1419, 1689, 12009, 18693, 28098
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,1
|
|
|
COMMENTS
|
Also numbers n such that (53*10^n-71)/9 is prime.
|
|
|
LINKS
|
Table of n, a(n) for n=1..13.
Makoto Kamada, Factorizations of 588...881.
Index entries for primes involving repunits.
|
|
|
MATHEMATICA
|
Do[ If[ PrimeQ[(53*10^n - 71)/9], Print[n]], {n, 0, 10000}]
|
|
|
CROSSREFS
|
Sequence in context: A192119 A050563 A168156 * A086189 A137082 A099414
Adjacent sequences: A103019 A103020 A103021 * A103023 A103024 A103025
|
|
|
KEYWORD
|
more,nonn
|
|
|
AUTHOR
|
Robert G. Wilson v, Jan 18 2005
|
|
|
EXTENSIONS
|
Addition of a(11)-a(13) from Kamada data by Robert Price, Dec 13 2010
|
|
|
STATUS
|
approved
|
| |
|
|
