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 A305658 #21 Feb 12 2021 12:10:16 %S A305658 1,20,2100,212000,210110000,21202200000,21200101000000, %T A305658 21011002020000000,2120220212100000000,2120012010112000000000, %U A305658 2101102110221110000000000,212211101110122200000000000,212001222211110201000000000000,210112102201222221020000000000000 %N A305658 Powers of 3 in base 3/2. %C A305658 a(n) has n zeros at the end. %C A305658 a(n) is A305659(n) with n zeros added at the end, where A305659(n) is powers of 2 in base 3/2. %H A305658 B. Chen, R. Chen, J. Guo, S. Lee et al., <a href="http://arxiv.org/abs/1808.04304">On Base 3/2 and its Sequences</a>, arXiv:1808.04304 [math.NT], 2018. %F A305658 a(n) = A024629(A000244(n)). %p A305658 b:= proc(n) `if`(n<1, 0, irem(n, 3, 'q')+b(2*q)*10) end: %p A305658 a:= n-> b(3^n): %p A305658 seq(a(n), n=0..20); # _Alois P. Heinz_, Jun 18 2018 %o A305658 (PARI) f(n) = if( n<1, 0, f(n\3 * 2) * 10 + n%3); %o A305658 a(n) = f(3^n); \\ _Michel Marcus_, Jun 18 2018 %Y A305658 Cf. A000244, A024629, A246435, A305659. %K A305658 nonn,base %O A305658 0,2 %A A305658 _Tanya Khovanova_ and PRIMES STEP Senior group, Jun 07 2018