|
| |
|
|
A059671
|
|
Numbers n such that n*10^n - 1 is prime.
|
|
13
|
|
|
|
2, 3, 8, 11, 15, 39, 60, 72, 77, 117, 183, 252, 396, 1745, 2843, 4665, 5364
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,1
|
|
|
COMMENTS
|
No further terms up to 500000 (see Harvey link). - Ray Chandler, Apr 10 2016
|
|
|
REFERENCES
|
J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 117, p. 41, Ellipses, Paris 2008.
|
|
|
LINKS
|
Table of n, a(n) for n=1..17.
Steven Harvey, Generalized Woodall Search
|
|
|
MATHEMATICA
|
Do[ If[ PrimeQ[ n*10^n - 1 ], Print[ n ] ], {n, 1, 2500} ]
|
|
|
PROG
|
(PARI) is(n)=ispseudoprime(n*10^n-1) \\ Charles R Greathouse IV, Mar 01 2017
|
|
|
CROSSREFS
|
Sequence in context: A173269 A050557 A039000 * A212771 A119116 A138756
Adjacent sequences: A059668 A059669 A059670 * A059672 A059673 A059674
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Robert G. Wilson v, Feb 05 2001
|
|
|
EXTENSIONS
|
a(15) - a(17) from Farideh Firoozbakht, Apr 01 2009
|
|
|
STATUS
|
approved
|
| |
|
|
