A155817 Sequence having the property that a(n) is the sum of the first a(n) digits of the sequence.

1, 10, 2, 4, 100, 101, 11, 12, 13, 14, 30, 1000, 10000, 40, 41, 100000, 102, 43, 60, 110, 1000000, 1001, 61, 80, 111, 100000000000, 90, 10000000, 103, 104, 10001, 1110, 112, 201, 108, 91, 95, 160, 161, 100000000000000000000000000000000000, 170, 1000001

Offset

1,2

Comments

From an idea of Eric Angelini. The condition of strict monotonicity is dropped with respect to A154328.

Links

Jon E. Schoenfield, Table of n, a(n) for n = 1..1000

Example

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.

Crossrefs

Cf. A154328.

Sequence in context: A169851 A161995 A069036 * A299980 A037922 A111287

Adjacent sequences: A155814 A155815 A155816 * A155818 A155819 A155820

Keyword

nonn,base

Author

Paolo P. Lava, Jan 28 2009

Extensions

Sequence corrected and extended by N. J. A. Sloane, Aug 31 2009, using terms from the b-file

Status

approved