%I #8 Feb 24 2017 02:54:21
%S 0,9,10,18,19,20,27,28,31,36,37,42,45,46,50,54,55,64,65,73,76,82,87,
%T 91,98,100,108,109,110,118,119,120,127,128,129,130,136,137,138,139,
%U 140,145,146,148,149,150,154,155,158,159,160,163,164,165,168,169,170,172,173
%N Slowest increasing sequence where some digit of a(n) and some digit of a(n+1) add up to 9.
%C Starting with another "seed" than 0 would produce another sequence.
%H Robert Israel, <a href="/A107433/b107433.txt">Table of n, a(n) for n = 0..10000</a>
%e After 28 we must have an integer containing a "7" (2+"7"=9) or a "1" (8+"1"=9). The smallest integer satisfying this constraint is 31 (and not 37 or 41 or any other containing a "7" or a "1")
%p f:= proc(n) local S, k;
%p S:= map(t -> 9-t, convert(convert(n,base,10),set));
%p for k from n+1 do
%p if convert(convert(k,base,10),set) intersect S <> {} then return k fi
%p od
%p end proc:
%p a[0]:= 0:
%p for n from 1 to 100 do a[n]:= f(a[n-1]) od:
%p seq(a[n],n=0..100); # _Robert Israel_, Feb 24 2017
%K base,easy,nonn
%O 0,2
%A _Eric Angelini_, Jun 09 2005
%E Corrected and extended by _Zak Seidov_, Jun 10 2005