A098729 Consider the sequence {b(n), n >= 1} of digits of the integers: 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 2 0... (A033307); a(n) = b(n) + n.

1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 12, 12, 14, 15, 16, 18, 18, 21, 20, 24, 22, 27, 24, 30, 26, 33, 28, 36, 30, 39, 33, 32, 35, 35, 37, 38, 39, 41, 41, 44, 43, 47, 45, 50, 47, 53, 49, 56, 51, 59, 54, 52, 56, 55, 58, 58, 60, 61, 62, 64, 64, 67, 66, 70, 68, 73, 70, 76, 72, 79, 75

Offset

1,2

Comments

Add its rank to each digit of the counting numbers (beginning with 0).

Links

Table of n, a(n) for n=1..71.

Example

The sequence of digits of the integers is
0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 2 0...
The 15th term, for instance, is a 1. Thus 1+15=16 is the 15th term of this sequence.
Next one is 2 (the digit) + 16 (the rank) = 18

Mathematica

dgs = Flatten[IntegerDigits/@Range[0, 50]]; Plus@@@Partition[Riffle[dgs, Range[Length[dgs]]], 2] (* Harvey P. Dale, Jan 15 2011 *)

Crossrefs

Sequence in context: A245234 A160144 A237292 * A160939 A160927 A240848

Adjacent sequences: A098726 A098727 A098728 * A098730 A098731 A098732

Keyword

base,nonn,easy

Author

Alexandre Wajnberg, Sep 30 2004

Extensions

More terms from Joshua Zucker, May 18 2006

Status

approved