|
|
A268061
|
|
Numbers k such that 7*8^k - 1 is prime.
|
|
4
|
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
a(10) > 2*10^5.
Terms are A001771(n)/3 that are integers.
|
|
REFERENCES
|
R. K. Guy, Unsolved Problems in Theory of Numbers, Section A3.
|
|
LINKS
|
|
|
MATHEMATICA
|
Select[Range[0, 200000], PrimeQ[7*8^# - 1] &]
|
|
PROG
|
(PARI) lista(nn) = for(n=1, nn, if(ispseudoprime(7*8^n-1), print1(n, ", "))) \\ Altug Alkan, Jan 25 2016
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,hard,more
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|