login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A023103 (10^n)-th digit of infinite string 12345678910111213141516... 3
1, 1, 5, 3, 7, 2, 1, 7, 8, 1, 1, 0, 1, 5, 7, 2, 6, 4, 3, 5, 3, 5, 4, 9, 6, 2, 4, 8, 7, 1, 1, 3, 7, 2, 3, 0, 8, 5, 3, 8, 2, 7, 6, 7, 9, 9, 2, 7, 0, 1, 6, 2, 0, 4, 1, 3, 8, 5, 3, 3, 3, 5, 0, 0, 1, 1, 5, 6, 1, 6, 2, 4, 3, 7, 5, 6, 8, 5, 3, 6, 8, 8, 2, 2, 0, 3, 9, 1, 8, 9, 2, 1, 1, 9, 6, 4, 4, 0, 2, 6, 4, 1, 0, 1, 4, 2, 8, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

In one of Ross Honsberger's "Mathematical Gems" series (Dolciani Mathematical Expositions, Mathematical Association of America) there is a formula for extracting the n-th digit. Would someone submit it? [Robert Wilson notes that the Mathemtica program below implements this formula.]

REFERENCES

M. Kraitchik, Mathematical Recreations. Dover, NY, 2nd ed., 1953, p. 49.

Unknown, Algorithms & Their Computer Solutions, p 160.

LINKS

Robert G. Wilson v, Table of n, a(n) for n = 0..1000

MATHEMATICA

almostNatural[n_, b_] := Block[{m = 0, d = n, i = 1, l, p}, While[m <= d, l = m; m = (b - 1) i*b^(i - 1) + l; i++]; i--; p = Mod[d - l, i]; q = Floor[(d - l)/i] + b^(i - 1); If[p != 0, IntegerDigits[q, b][[p]], Mod[q - 1, b]]]; Array[ almostNatural[10^#, 10] &, 105, 0] (* modified by Robert G. Wilson v, Jul 15 2014 *)

CROSSREFS

10^n-th digit in the almost natural number (A007376).

Cf. Champernowne constant or Mahler's number A033307.

Cf. A033713.

Sequence in context: A065169 A247617 A099217 * A153454 A198877 A201752

Adjacent sequences:  A023100 A023101 A023102 * A023104 A023105 A023106

KEYWORD

nonn,base

AUTHOR

David W. Wilson

EXTENSIONS

Edited by Robert G. Wilson v, Jun 18 2002

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 25 13:31 EDT 2019. Contains 322461 sequences. (Running on oeis4.)