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 A145506 #6 Jun 11 2024 00:20:19
%S A145506 6,46,2206,4870846,23725150497406,562882766124611619513723646,
%T A145506 316837008400094222150776738483768236006420971486980606
%N A145506 a(n+1) = a(n)^2+2*a(n)-2 and a(1)=6.
%C A145506 General formula for a(n+1) = a(n)^2+2*a(n)-2 and a(1) = k+1 is a(n) = floor(((k + sqrt(k^2 + 4))/2)^(2^((n+1) - 1))).
%C A145506 Essentially the same as A145502. - _R. J. Mathar_, Mar 18 2009
%t A145506 aa = {}; k = 6; Do[AppendTo[aa, k]; k = k^2 + 2 k - 2, {n, 1, 10}]; aa
%t A145506 or
%t A145506 k = 5; Table[Floor[((k + Sqrt[k^2 + 4])/2)^(2^(n - 1))], {n, 2, 7}] (* Artur Jasinski *)
%Y A145506 Cf. A145502-A145511.
%K A145506 nonn
%O A145506 1,1
%A A145506 _Artur Jasinski_, Oct 11 2008