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 A215092 #13 Sep 08 2022 08:46:03
%S A215092 1,2,3,4,5,3,4,5,6,7,8,6,7,8,9,10,11,9,10,11,12,13,14,12,13,14,15,16,
%T A215092 17,15,16,17,18,19,20,9,10,11,12,13,14,12,13,14,15,16,17,15,16,17,18,
%U A215092 19,20,18,19,20,21,22,23,21,22,23,24,25,26,24,25,26,27,28,29,18
%N A215092 a(n) = Sum_{i=0..m} d(i)*3^i, where Sum_{i=0..m} d(i)*6^i is the base-6 representation of n.
%H A215092 Clark Kimberling, <a href="/A215092/b215092.txt">Table of n, a(n) for n = 1..1000</a>
%F A215092 a(n) = 3*a(n/6) if n == 0 (mod 6); otherwise a(n) = a(n-1)+1.
%t A215092 Table[FromDigits[RealDigits[n, 6], 3], {n, 0, 100}]
%o A215092 (Magma) [n eq 1 select 1 else n mod 6 eq 0 select 3*Self(n div 6) else Self(n-1)+1: n in [1..72]]; // _Bruno Berselli_, Jan 25 2018
%Y A215092 Cf. A037454.
%K A215092 nonn,base,easy
%O A215092 1,2
%A A215092 _Clark Kimberling_, Aug 13 2012