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A081665
Smallest integer q for which there exists a fraction p/q containing n in its decimal expansion.
1
1, 4, 3, 5, 2, 3, 4, 5, 10, 1, 9, 8, 15, 7, 13, 6, 17, 11, 21, 5, 14, 9, 13, 25, 4, 15, 11, 7, 17, 10, 16, 25, 3, 23, 14, 11, 8, 13, 23, 5, 12, 7, 16, 9, 11, 13, 17, 25, 51, 2, 27, 17, 13, 11, 9, 16, 7, 12, 22, 5, 13, 8, 11, 14, 20, 3, 28, 16, 13, 10, 7, 11, 15, 27, 4, 13, 9, 14, 24, 5, 11
OFFSET
1,2
COMMENTS
Inspired by problem 14 on the 2003 American Invitational Mathematics Examination, which asked for a(251). There are some slightly different versions of this sequence. For example, you could consider 1/2 = .5 or 1/2 = .50000...; I chose the latter interpretation here.
LINKS
American Mathematics Competitions, Problem 14
EXAMPLE
a(6) = 3 because 2/3 = .6...; a(42) = 7 because 1/7 = .142...
CROSSREFS
A081664 gives the numerators.
Sequence in context: A011397 A352692 A339579 * A131911 A254037 A321154
KEYWORD
base,frac,nonn
AUTHOR
Joshua Zucker, Mar 26 2003
STATUS
approved