

A098728


Consider the sequence {b(n), n >= 1} of digits of the natural (or counting) numbers: 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... (A007376); a(n) = n  b(n).


2



0, 0, 0, 0, 0, 0, 0, 0, 0, 9, 11, 11, 12, 13, 13, 15, 14, 17, 15, 19, 16, 21, 17, 23, 18, 25, 19, 27, 20, 28, 31, 30, 32, 32, 33, 34, 34, 36, 35, 38, 36, 40, 37, 42, 38, 44, 39, 46, 40, 47, 51, 49, 52, 51, 53, 53, 54, 55, 55, 57, 56, 59, 57, 61, 58, 63, 59, 65, 60, 66, 71, 68, 72
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OFFSET

0,10


COMMENTS

Subtract each digit of the counting numbers from its rank.


LINKS



EXAMPLE

The sequence of digits of the counting numbers is
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 2. Thus 152=13 is the 15th term of this sequence.
Next one is a 1, thus 16 (the rank)  1 (the 16th digit of the decimal expansion of the counting numbers) = 15, which is the 16th term of this sequence.
Next one is 173=14


MATHEMATICA

With[{c=Flatten[IntegerDigits/@Range[70]]}, #[[1]]#[[2]]&/@Partition[ Riffle[ Range[Length[c]], c], 2]] (* Harvey P. Dale, Aug 07 2019 *)


CROSSREFS



KEYWORD

base,easy,nonn


AUTHOR



EXTENSIONS

More terms from Stacy Hawthorne (shawtho1(AT)ashland.edu), Jan 12 2006


STATUS

approved



