This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A330831 #23 Jan 16 2020 13:24:33 %S A330831 64,576,82944,4362338304,18447869990796263424 %N A330831 a(n) = (F_n^2 - 1)^2, where F_n is a Fermat prime, A019434. %C A330831 Also the second element of the power-spectral basis of A330829. %C A330831 The first element of the power-spectral basis of A330829 is A330830. %F A330831 a(n) = (F(n)^2 - 1)^2, where F(n) = 2^(2^n)+1 is a Fermat prime. %e A330831 a(0) = (3^2 - 1)^2 = 64. %p A330831 F := proc(n) return 2^(2^n)+1 end; %p A330831 a := proc(n) if isprime(F(n)) then return (F(n)^2-1)^2 fi; end; %p A330831 [seq(a(n),n=0..4)]; %Y A330831 Cf. A000215, A001146, A019434, A330827, A330828, A330829, A330830. %K A330831 nonn %O A330831 1,1 %A A330831 _Walter Kehowski_, Jan 06 2020