%I #10 Jun 10 2016 00:20:59

%S 1,10,19,9,18,8,17,7,16,6,15,5,14,4,13,3,12,2,11,29,20,101,28,26,24,

%T 22,110,37,21,100,46,31,30,102,55,23,111,38,35,32,120,39,27,25,41,40,

%U 103,64,33,201,200,299,36,42,112,47,34,121,48,44,130,49,45,50,104,73,43,202

%N a(n) shows the digit sum of the smallest a(n+1) not yet present in the sequence

%C a(1) = 1, and for n > 1 a(n) is the smallest integer not yet present in the sequence with digital sum a substring of the decimal digits of a(n-1).

%H Charles R Greathouse IV, <a href="/A173822/b173822.txt">Table of n, a(n) for n=1..10000</a>

%H Eric Angelini, <a href="http://www.cetteadressecomportecinquantesignes.com/DigitsumVIS.htm">Visible DigitSums</a> (sequence T)

%H E. Angelini, <a href="/A173821/a173821.pdf">Visible DigitSums</a> [Cached copy, with permission]

%e a(1) is 1, so a(2) must have digital sum 1, so a(2) = 10 (1 is already in the sequence). a(3) must then have digital sum 1, 0, or 10, so a(3) = 19. a(4) must have digital sum 1, 9, or 19 and so a(4) = 9.

%Y Cf. A173821, A173823.

%K base,nonn,look

%O 1,2

%A _Charles R Greathouse IV_ and _Eric Angelini_, Mar 01 2010