A155817 - OEIS

%I #14 Jun 07 2018 02:58:05

%S 1,10,2,4,100,101,11,12,13,14,30,1000,10000,40,41,100000,102,43,60,

%T 110,1000000,1001,61,80,111,100000000000,90,10000000,103,104,10001,

%U 1110,112,201,108,91,95,160,161,100000000000000000000000000000000000,170,1000001

%N Sequence having the property that a(n) is the sum of the first a(n) digits of the sequence.

%C From an idea of _Eric Angelini_. The condition of strict monotonicity is dropped with respect to A154328.

%H Jon E. Schoenfield, <a href="/A155817/b155817.txt">Table of n, a(n) for n = 1..1000</a>

%e We start with a(1)=1. The next term a(2) cannot be 2,...,9 because the sum of these digits would be larger: the least possibility not leading to a contradiction is a(2)=10. Then we can go on with a(3)=2 because the sum of the first two digits, 1=a(1) and 1 from 10=a(2), is equal to 2. Then a(4)=4 because sum of the first 4 digits, 1+1+0+2, is equal to 4.

%Y Cf. A154328.

%K nonn,base

%O 1,2

%A _Paolo P. Lava_, Jan 28 2009

%E Sequence corrected and extended by _N. J. A. Sloane_, Aug 31 2009, using terms from the b-file