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 A223079 #6 Mar 20 2013 15:27:16 %S A223079 1023,10323,103323,1033323,10231023,10333323,102301023,103333323, %T A223079 1023001023,1032310323,1033333323,10230001023,10323010323,10333333323, %U A223079 102300001023,102310231023,103230010323,103323103323,103333333323 %N A223079 Positive integers, written in base 4, with the property that if the base-4 representation is reversed the result is three times the original number. %C A223079 For the decimal representations of these numbers see A223078. %Y A223079 Cf. A173951, A214927, A223078. %K A223079 nonn,base %O A223079 1,1 %A A223079 _N. J. A. Sloane_, Mar 14 2013