login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A275783 Numbers n such that 10^n + 9^(n+1) is prime. 0
2, 3, 6, 11, 44, 64, 83, 123, 166, 381, 446, 1221, 1540, 3156, 5117, 5476, 6291, 6353, 13053, 15158, 23904, 78288, 82254, 91230 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
a(25) > 10^5.
LINKS
EXAMPLE
3 is a member since 10^3 + 9^4 = 1000 + 6561 = 7561 which is a prime number.
MATHEMATICA
Select[Range[0, 100000], PrimeQ[10^# + 9^(# + 1)] &]
PROG
(PARI) is(n)=ispseudoprime(10^n+9^(n+1)) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Sequence in context: A102952 A369223 A065653 * A102021 A350911 A144641
KEYWORD
nonn,more
AUTHOR
Robert Price, Aug 08 2016
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 11:59 EDT 2024. Contains 371254 sequences. (Running on oeis4.)