A209901 - OEIS

%I #19 Sep 26 2015 14:41:27

%S 11,125,9029,543605,1614529685,83828316389,215703854542469,

%T 10789535445362645,26579017117027313525,3183060102526390833854309,

%U 156448938516521406467644085,18500229372226631089176131976869,44487435359130133495783012898708549

%N 7^p - 6^p - 2 with p = prime(n).

%C After 11 and 9029, there are no prime values of a(n) through 7^109 - 6^109 - 2.

%H Vincenzo Librandi, <a href="/A209901/b209901.txt">Table of n, a(n) for n = 1..100</a>

%F a(n) = A016169(A000040(n)) - 2 = A204768(n) - 1 = A000420(A000040(n)) - A000400(A000040(n)) - 2.

%e 543605 is in the sequence because 543605 = 7^7 - 6^7 - 2, and 7 is prime.

%t Table[7^p - 6^p - 2, {p, Prime[Range[20]]}] (* _T. D. Noe_, Mar 15 2012 *)

%o (PARI) forprime(p=2,100,print1(7^p-6^p-2", ")) \\ _Charles R Greathouse IV_, Mar 15 2012

%Y Cf. A000040, A000400, A000420, A016169, A204768.

%K nonn,easy,less

%O 1,1

%A _Jonathan Vos Post_, Mar 14 2012