|
| |
|
|
A099017
|
|
Numbers n such that 4*10^n + 6*R_n + 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.
|
|
1
|
|
|
|
1, 2, 6, 10, 12, 13, 22, 32, 46, 61, 68, 90, 110, 652, 1608, 1904, 2003, 3038, 3086, 9580, 9698, 10639, 14461
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,2
|
|
|
COMMENTS
|
Also numbers n such that (14*10^n+1)/3 is prime.
No others less than 450.
|
|
|
LINKS
|
Table of n, a(n) for n=1..23.
Makoto Kamada, Factorizations of 466...667.
Index entries for primes involving repunits.
|
|
|
EXAMPLE
|
n = 1, 2, 6 are members since 47, 467, 4666667 are primes.
|
|
|
MATHEMATICA
|
Do[ If[ PrimeQ[(14*10^n + 1)/3], Print[n]], {n, 0, 10000}] (from Robert G. Wilson v Jan 17 2005)
|
|
|
CROSSREFS
|
Cf. A099005, A098959.
Sequence in context: A085258 A175437 A133520 * A139799 A214586 A139710
Adjacent sequences: A099014 A099015 A099016 * A099018 A099019 A099020
|
|
|
KEYWORD
|
more,nonn
|
|
|
AUTHOR
|
Julien Peter Benney (jpbenney(AT)ftml.net), Nov 13 2004
|
|
|
EXTENSIONS
|
a(14) - a(21) from Robert G. Wilson v, Jan 17 2005
a(22)-a(23) from Kamada data by Robert Price, Dec 08 2010
|
|
|
STATUS
|
approved
|
| |
|
|
