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 A140134 #8 Oct 08 2012 15:52:18 %S A140134 1,2,4,8,16,32,63,126,252,504,1008,2016,4032,8001,16002,32004,63000, %T A140134 126000,252000,504000,1008000,2016000,4032000,8001000,16002000, %U A140134 32004000,63000000,126000000,252000000,504000000,1008000000,2016000000 %N A140134 a(n)=2a(n-1) but when sum of digits of 2a(n-1) is greater than 9 take a(n) = largest number < 2a(n-1) which has sum of digits = 9. %e A140134 a(12)=4032; 2*4032 = 8064; digit sum is 18; decrease until we get a number with digit sum 9, which is 8001; so a(13) = 8001. - From _N. J. A. Sloane_, Oct 08 2012 %Y A140134 Cf. A062259. %K A140134 nonn,base %O A140134 0,2 %A A140134 _Paul Curtz_, Jun 15 2008 %E A140134 Keyword base added by _Reinhard Zumkeller_, Feb 25 2010