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 A138167 #5 Mar 30 2012 18:50:59 %S A138167 1,5,6,7,8,9,10,11,12,21,31,36,37,38,39,40,41,42,43,44,49,58,66,67,68, %T A138167 76,86,95,96,97,98,104,113,122,123,124,125,126,127,128,129,130,131, %U A138167 132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149 %N A138167 Numbers containing their length in ternary representation. %H A138167 R. Zumkeller, <a href="/A138167/b138167.txt">Table of n, a(n) for n = 1..10000</a> %e A138167 42 ->'1120', length = 4 ->'11', therefore 42 is a term; %e A138167 420 ->'120120', length = 6 ->'20', therefore 420 is a term. %Y A138167 Cf. A081604, A138166, A138168. %K A138167 nonn,base %O A138167 1,2 %A A138167 _Reinhard Zumkeller_, Mar 03 2008