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%I #4 Sep 10 2016 14:08:28
%S 15,171,28563,815730723,665416609183179843,
%T 442779263776840698304313192148785283,
%U 196053476430761073330659760423566015424403280004115787589590963842248963
%N Numbers of the form 13^(2^n) + 2.
%C These numbers are divisible by 3. Expanding the binomial (12+1)^(2^n)+1 we
%C get 12h+1+2 for some h and 12h+3 is divisible by 3.
%F a(n) = A176596(n)+2. - _R. J. Mathar_, Sep 10 2016
%o (PARI) g(a,n) = if(a%2,b=2,b=1);for(x=0,n,y=a^(2^x)+b;print1(y","))
%K nonn
%O 1,1
%A _Cino Hilliard_, Dec 08 2008
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