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%I #6 Jun 03 2020 10:46:17
%S 2,38,20918,8033210678,1225424537811128774198,
%T 28531636118039771088818247968115767751133238,
%U 15467030931872204052220217595650084422758156440239110185314071903881367885819214004747318
%N a(n)=(2^(2^n) + 3^(2^n) + 5^(2^n))/19
%C The next term (a(8)) has 178 digits. - _Harvey P. Dale_, Jun 03 2020
%t f[n_] := Module[{c = 2^n}, (2^c + 3^c + 5^c)/19]; Array[f,7] (* _Harvey P. Dale_, Jun 03 2020 *)
%o (PARI) a(n)=(2^(2^n) + 3^(2^n) + 5^(2^n))/19
%K nonn
%O 1,1
%A _Alexander R. Povolotsky_, Nov 11 2007