A330831 - OEIS

%I #23 Jan 16 2020 13:24:33

%S 64,576,82944,4362338304,18447869990796263424

%N a(n) = (F_n^2 - 1)^2, where F_n is a Fermat prime, A019434.

%C Also the second element of the power-spectral basis of A330829.

%C The first element of the power-spectral basis of A330829 is A330830.

%F a(n) = (F(n)^2 - 1)^2, where F(n) = 2^(2^n)+1 is a Fermat prime.

%e a(0) = (3^2 - 1)^2 = 64.

%p F := proc(n) return 2^(2^n)+1 end;

%p a := proc(n) if isprime(F(n)) then return (F(n)^2-1)^2 fi; end;

%p [seq(a(n),n=0..4)];

%Y Cf. A000215, A001146, A019434, A330827, A330828, A330829, A330830.

%K nonn

%O 1,1

%A _Walter Kehowski_, Jan 06 2020