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 A001128 #17 Mar 18 2017 05:17:43
%S A001128 2,4,16,976,662704,269896807264,124883600543123110859968,
%T A001128 108643488775144622666209173128243503963147630528
%N A001128 Reverse digits of previous term and multiply by previous term.
%H A001128 John Cerkan, <a href="/A001128/b001128.txt">Table of n, a(n) for n = 1..12</a>
%F A001128 a(n) = A061205(a(n-1)) for n>1, with a(1) = 2. - _Michel Marcus_, Mar 18 2017
%t A001128 a[n_]:=If[n<2, 2,a[n - 1] * FromDigits[Reverse[IntegerDigits[a[n - 1]]]]]; Table[a[n], {n, 10}] (* _Indranil Ghosh_, Mar 18 2017 *)
%o A001128 (PARI) a(n) = if (n==1, 2, prev = a(n-1); prev*fromdigits(Vecrev(digits(prev)))); \\ _Michel Marcus_, Mar 18 2017
%o A001128 (Python) def a(n): return 2 if n<2 else a(n - 1) * int(str(a(n - 1))[::-1]) # _Indranil Ghosh_, Mar 18 2017
%Y A001128 Cf. A061205.
%K A001128 nonn,base
%O A001128 1,1
%A A001128 _N. J. A. Sloane_