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 A259988 #17 Jul 18 2015 16:59:40 %S A259988 3,13,213,213,50213,350213,1350213,21350213,221350213,2221350213, %T A259988 52221350213,152221350213,5152221350213,55152221350213, %U A259988 155152221350213,4155152221350213,14155152221350213,314155152221350213,1314155152221350213,21314155152221350213 %N A259988 This sequence and A259989 are base-6 analogs of A007185 and A016090, written in base 6. %C A259988 See Schut (1991) for precise definition. %C A259988 Ignoring repetitions, the subsequence of A201821 of terms ending in 3. - _Eric M. Schmidt_, Jul 18 2015 %D A259988 C. P. Schut, Idempotents. Report AM-R9101, Centrum voor Wiskunde en Informatica, Amsterdam, 1991. %H A259988 Eric M. Schmidt, <a href="/A259988/b259988.txt">Table of n, a(n) for n = 1..1000</a> %o A259988 (Sage) def a(n) : return Integer(crt(1, 0, 2^n, 3^n).str(6)) # _Eric M. Schmidt_, Jul 18 2015 %Y A259988 Cf. A007185, A016090, A201821, A237583, A259986-A259991. %K A259988 nonn,base %O A259988 1,1 %A A259988 _N. J. A. Sloane_, Jul 13 2015 %E A259988 More terms from _Eric M. Schmidt_, Jul 18 2015