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A078268
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Smallest integer which is an integer multiple of the number N obtained by placing the string "n" after a decimal point.
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4
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1, 1, 3, 2, 1, 3, 7, 4, 9, 1, 11, 3, 13, 7, 3, 4, 17, 9, 19, 1, 21, 11, 23, 6, 1, 13, 27, 7, 29, 3, 31, 8, 33, 17, 7, 9, 37, 19, 39, 2, 41, 21, 43, 11, 9, 23, 47, 12, 49, 1, 51, 13, 53, 27, 11, 14, 57, 29, 59, 3, 61, 31, 63, 16, 13, 33, 67, 17, 69, 7, 71, 18, 73, 37, 3, 19, 77, 39, 79
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OFFSET
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1,3
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COMMENTS
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Numerator of n/10^k, where k is the number of digits in n. - Dean Hickerson, Mar 21 2003
a(p) = p if p is a prime other than 2 and 5.
Smallest integer m such that the concatenation of decimal representations of m and n is a multiple of n. - Reinhard Zumkeller, Mar 19 2003
a(n) = numerator of fraction a/b, where gcd(a, b) = 1, such that its decimal representation has the form 0.(n). Denominators in A078267: 10, 5, 10, 5, 2, 5, 10, 5, 10, 10, 100, ... Example: a(6) = 3; 3/5 = 0.6. - Jaroslav Krizek, Feb 05 2010
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LINKS
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FORMULA
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EXAMPLE
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a(40)=2 since writing 40 after the decimal point gives 0.40 and 2 is the smallest integer multiple of 0.4.
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MAPLE
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a:= n -> numer(n/10^(1+ilog10(n))):
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MATHEMATICA
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si[n_]:=Module[{c=n/10^IntegerLength[n], m=1}, While[!IntegerQ[c*m], m++]; c*m]; Array[si, 80] (* Harvey P. Dale, Apr 06 2013 *)
Table[n/GCD[n, 10^(1 + Floor[Log10[n]])], {n, 79}] (* L. Edson Jeffery, Jul 25 2014 *)
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PROG
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(PARI) a(n) = numerator(n/10^(#Str(n))); \\ Michel Marcus, Mar 31 2019
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CROSSREFS
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KEYWORD
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base,frac,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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