A161995 a(n) represents the minimum number k, not already present in the sequence, whose digit sum is equal to the digital root of Sum_{j=0..n-1} a(j), with a(0)=0 and a(1)=1.

0, 1, 10, 2, 4, 8, 7, 5, 100, 11, 13, 17, 16, 14, 1000, 20, 22, 26, 25, 23, 10000, 101, 31, 35, 34, 32, 100000, 110, 40, 44, 43, 41, 1000000, 200, 103, 53, 52, 50, 10000000, 1001, 112, 62, 61, 104, 100000000, 1010, 121, 71, 70, 113, 1000000000, 1100, 130, 80, 106

Offset

0,3

Comments

From a(3) onward the digital root is periodic with period length equal to six: 1,2,4,8,7,5.

Links

Table of n, a(n) for n=0..54.

Example

a(3) = 10 because a(0) + a(1) = 1 and 10 is the minimum number greater than 1 whose digit sum is equal to 1.

Crossrefs

Cf. A010888.

Sequence in context: A049296 A220468 A169851 * A069036 A155817 A299980

Adjacent sequences: A161992 A161993 A161994 * A161996 A161997 A161998

Keyword

easy,nonn,base

Author

Paolo P. Lava & Giorgio Balzarotti, Jun 24 2009

Status

approved