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 A004645 #16 Sep 08 2022 08:44:33
%S A004645 1,2,4,12,24,52,144,332,1104,2212,4424,13252,30544,101532,203504,
%T A004645 411412,1223224,2450452,5341344,15123132,34250304,112541012,225522024,
%U A004645 455444052,1355332144,3155104332,10354213104
%N A004645 Powers of 2 written in base 6.
%H A004645 Vincenzo Librandi, <a href="/A004645/b004645.txt">Table of n, a(n) for n = 0..1000</a>
%t A004645 Table[FromDigits[IntegerDigits[2^n, 6]], {n, 0, 40}] (* _Vincenzo Librandi_, Jun 07 2013 *)
%o A004645 (PARI) a(n)=fromdigits(digits(2^n,6)) \\ _M. F. Hasler_, Jun 23 2018
%o A004645 (Magma) [Seqint(Intseq(2^n, 6)): n in [0..30]]; // _G. C. Greubel_, Sep 10 2018
%Y A004645 Cf. A000079, A004642, ..., A004655: powers of 2 written in base 10, 3, 4, ..., 16
%Y A004645 Cf. A000244, A004656, A004658, A004659, ... : powers of 3 written in base 10, 2, 4, 5, ...
%K A004645 nonn,base,easy
%O A004645 0,2
%A A004645 _N. J. A. Sloane_