The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A176779 Smallest number appearing exactly n times in the concatenation of all integers from 1 to itself. 0
1, 12, 121, 1011, 1121, 10111, 11121, 109911, 111311, 111211, 1101111, 1112211, 1111211, 11011111, 11192111, 11111211, 11112111, 111011111, 111113111, 111122111, 111112111, 1110111111, 1111122111, 1111921111, 1111112111 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
For m>1, is the number of m-digit terms in the sequence always Int(m/2)?
For 4<=m<=10, the last m-digit term consists of m-1 1's and a single 2 located at the first digit position to the right of the middle, i.e., 1121, 11121, 111211, 1111211, 11112111, 111112111, 1111121111. Does this pattern hold for all m>3?
Is there an easy way to extend the sequence indefinitely?
LINKS
EXAMPLE
Let s(k) be the string of digits obtained by concatenating all integers from 1 to k. Then a(3)=121 because the substring 121 appears exactly 3 times in s(121)=123..1213..112113..119120121, and there is no smaller number having this property.
CROSSREFS
Sequence in context: A299823 A222634 A018204 * A098297 A037543 A214317
KEYWORD
base,nonn
AUTHOR
Jon E. Schoenfield, Apr 25 2010
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 16 11:09 EDT 2024. Contains 373429 sequences. (Running on oeis4.)