OFFSET
1,1
COMMENTS
Related to a problem posed by Google and discussed on the MathWorld link.
Together with the b-file, this gives the complete list of all 47 positive numbers n such that n is equal to the number of 4's in the decimal digits of all numbers <= n. - Daniel Hirschberg (dan(AT)ics.uci.edu), May 05 2007
LINKS
Daniel Hirschberg (dan(AT)ics.uci.edu), May 05 2007, Table of n, a(n) for n = 1..47
Tanya Khovanova and Gregory Marton, Archive Labeling Sequences, arXiv:2305.10357 [math.HO], 2023. See p. 4.
Mathworld, Problem 17 of Google Labs Aptitude Test Partially Answered, MathWorld Headline News, October 13 2004.
FORMULA
a(n) = 499999983 + n, n <= 10; a(n) = 500000000, n = 11
EXAMPLE
a(1) = 499999984, since writing out all numbers from 0 to 499999984 requires that 499999984 4's be used and since 499999984 is the first such positive integer.
a(4) = 499999987 because the number of 4's in the decimal digits of the numbers from 1 to 499999987 is 499999987 and this is the 4th such number.
CROSSREFS
KEYWORD
nonn,base,fini,full
AUTHOR
Ryan Propper, Dec 11 2004
EXTENSIONS
More terms from Daniel Hirschberg (dan(AT)ics.uci.edu), May 05 2007
Keyword added by Charles R Greathouse IV, Jul 22 2010
STATUS
approved