A093612 Primes of form 7^n-2.

5, 47, 2399, 823541, 5764799, 13841287199, 4747561509941, 459986536544739960976799, 157775382034845806615042741, 97327453648743672783790144527749033795901408624680013074608083129650399

Offset: 1

Author

Arnaud Vernier, May 23 2004

Keywords

• nonn

Comments

The exponents n are listed in A090669, cf. formula. [From M. F. Hasler, Nov 26 2009]

The next term (a(11)) has 83 digits. - Harvey P. Dale, Nov 14 2014

Crossrefs

Cf. A014232.

Programs

Mathematica

Select[7^Range[90]-2,PrimeQ] (* Harvey P. Dale, Nov 14 2014 *)

Formula

a(n)=7^A090669(n)-2. [From M. F. Hasler, Nov 26 2009]

Extensions

Terms beyond a(6) from M. F. Hasler, Nov 26 2009