|
| |
|
|
A183177
|
|
Numbers n such that (10^(2n+1)+15*10^n-1)/3 is prime.
|
|
2
|
| |
|
|
|
OFFSET
|
1,2
|
|
|
COMMENTS
|
a(11) > 10^5. - Robert Price, Apr 21 2016
|
|
|
REFERENCES
|
C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.
|
|
|
LINKS
|
Table of n, a(n) for n=1..10.
Patrick De Geest, World!Of Numbers, Palindromic Wing Primes (PWP's)
Makoto Kamada, Prime numbers of the form 33...33833...33
Index entries for primes involving repunits.
|
|
|
FORMULA
|
a(n) = (A077792(n)-1)/2.
|
|
|
MATHEMATICA
|
Do[If[PrimeQ[(10^(2n + 1) + 15*10^n - 1)/3], Print[n]], {n, 3000}]
|
|
|
PROG
|
(PARI) is(n)=ispseudoprime((10^(2*n+1)+15*10^n-1)/3) \\ Charles R Greathouse IV, Jun 13 2017
|
|
|
CROSSREFS
|
Cf. A004023, A077775-A077798, A107123-A107127, A107648, A107649, A115073, A183174-A183187.
Sequence in context: A172455 A258174 A254569 * A058795 A027459 A329108
Adjacent sequences: A183174 A183175 A183176 * A183178 A183179 A183180
|
|
|
KEYWORD
|
nonn,more,base
|
|
|
AUTHOR
|
Ray Chandler, Dec 28 2010
|
|
|
EXTENSIONS
|
a(10) from Robert Price, Apr 21 2016
|
|
|
STATUS
|
approved
|
| |
|
|
