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 A103162 #7 Dec 12 2021 20:13:10
%S A103162 3,9,18,18,9,9,36,9,27,27,9,9,9,9,9,27,9,63,9,9,9,9,27,18,36,9,9,18,
%T A103162 18,18,9,9,9,9,4941,9,9,9,9,9,9,9,9,9,144,18,9,153,333,63,18,9,27,9,9,
%U A103162 9,9,9,9,9,9,9,9,9,9,9,9,18,18,9,9,18,18,18,9,9,9,9,9,9,9,9,9,81,9,9,9,9,54
%N A103162 GCD of reverse(3^n) and reverse(3^(n+1)).
%F A103162 a(n) = GCD(A004167(n), A004167(n+1)).
%e A103162 These common divisors are always divisible by 3.
%t A103162 rd[x_] :=FromDigits[Reverse[IntegerDigits[x]]] Table[GCD[rd[3^w], rd[3^(w+1)]], {w, 1, 100}]
%Y A103162 Cf. A004167.
%K A103162 base,nonn
%O A103162 1,1
%A A103162 _Labos Elemer_, Jan 25 2005