login
Primes of form 7^n-2.
1

%I #9 Nov 14 2014 18:06:25

%S 5,47,2399,823541,5764799,13841287199,4747561509941,

%T 459986536544739960976799,157775382034845806615042741,

%U 97327453648743672783790144527749033795901408624680013074608083129650399

%N Primes of form 7^n-2.

%C The exponents n are listed in A090669, cf. formula. [From _M. F. Hasler_, Nov 26 2009]

%C The next term (a(11)) has 83 digits. - _Harvey P. Dale_, Nov 14 2014

%F a(n)=7^A090669(n)-2. [From _M. F. Hasler_, Nov 26 2009]

%t Select[7^Range[90]-2,PrimeQ] (* _Harvey P. Dale_, Nov 14 2014 *)

%Y Cf. A014232.

%K nonn

%O 1,1

%A _Arnaud Vernier_, May 23 2004

%E Terms beyond a(6) from _M. F. Hasler_, Nov 26 2009