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 A045539 #18 Jan 01 2021 08:06:37
%S A045539 1,5,52,62,13,56,82,14,7,53,562,182,19,59,592,692,643,5123,51652,
%T A045539 62852,62413,560213,5601082,1450082,140527,536207,5301862,1390562,
%U A045539 182596,89219,590644,223592,697111,5555843,51297772,68884652,62324443,512226113,5650311652
%N A045539 Multiply by 5 and reverse.
%H A045539 Alois P. Heinz, <a href="/A045539/b045539.txt">Table of n, a(n) for n = 0..1000</a>
%H A045539 Vaclav Kotesovec, <a href="/A045539/a045539_1.jpg">Plot of a(n)^(1/n) for n = 0..100000</a>
%p A045539 a:= proc(n) option remember; `if`(n=0, 1,
%p A045539 (s-> parse(cat(s[-i]$i=1..length(s))))(""||(5*a(n-1))))
%p A045539 end:
%p A045539 seq(a(n), n=0..40); # _Alois P. Heinz_, Apr 09 2015
%t A045539 a[n_] := a[n] = If[n==0, 1, IntegerReverse[5a[n-1]]];
%t A045539 a /@ Range[0, 40] (* _Jean-François Alcover_, Jan 01 2021 *)
%Y A045539 Cf. A036447 (*2), A163632 (*3), A132064 (*4), A132078 (*6), A132114 (*7), A132113 (*8), A133361 (*9).
%K A045539 base,nonn
%O A045539 0,2
%A A045539 _Erich Friedman_