|
|
A180745
|
|
Numbers k such that 7^k - 5^k + 1 is prime.
|
|
0
|
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
|
|
LINKS
|
|
|
MATHEMATICA
|
Select[Range[5000], PrimeQ[7^#-5^#+1]&] (* Harvey P. Dale, Jan 25 2011 *)
|
|
PROG
|
(Magma) [n: n in [0..1000]|IsPrime(7^n-5^n+1)]
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,hard,more
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|