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 A037470 #20 Jan 04 2016 14:55:29
%S A037470 0,1,2,3,4,5,7,8,9,10,11,12,14,15,16,17,18,19,21,22,23,24,25,26,28,29,
%T A037470 30,31,32,33,35,36,37,38,39,40,49,50,51,52,53,54,56,57,58,59,60,61,63,
%U A037470 64,65,66,67,68,70,71,72,73,74,75,77,78,79,80,81,82,84,85,86
%N A037470 a(n)=Sum{d(i)*7^i: i=0,1,...,m}, where Sum{d(i)*6^i: i=0,1,...,m} is the base 6 representation of n.
%C A037470 Except for the offset, identical to A020657: a(n)=A020657(n+1). - _M. F. Hasler_, Oct 05 2014
%H A037470 Clark Kimberling, <a href="/A037470/b037470.txt">Table of n, a(n) for n = 0..1000</a>
%t A037470 Table[FromDigits[RealDigits[n, 6], 7], {n, 0, 100}] (* _Clark Kimberling_, Aug 14 2012 *)
%o A037470 (PARI) a(n)=vector(#n=digits(n, 6), i, 7^(#n-i))*n~ \\ _M. F. Hasler_, Oct 05 2014
%Y A037470 Essentially a duplicate of A020657. - _N. J. A. Sloane_, Jan 04 2016
%K A037470 nonn,base
%O A037470 0,3
%A A037470 _Clark Kimberling_
%E A037470 Offset changed to 0 by _Clark Kimberling_, Aug 14 2012