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

 


A272345
Numbers n such that 8^n-7^(n-1) is prime.
1
1, 3, 5, 29, 41, 83, 471, 725, 1277, 10271, 15069, 97731
OFFSET
1,2
COMMENTS
a(13) > 10^5.
EXAMPLE
5 is a member since 8^5 - 7^4 = 32768 - 2401 = 30367 which is a prime number.
MATHEMATICA
Select[Range[0, 100000], PrimeQ[8^# - 7^(# - 1)] &]
PROG
(PARI) is(n)=ispseudoprime(8^n-7^(n-1)) \\ Charles R Greathouse IV, Jun 13 2017
KEYWORD
nonn,more
AUTHOR
Robert Price, Apr 26 2016
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | 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 September 20 03:37 EDT 2024. Contains 376016 sequences. (Running on oeis4.)