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 A172498 a(n) = denominator of fraction a/b, where gcd(a, b) = 1, whose decimal representation has the form 0.(1)(2)(3)...(n-1)(n)... with period (1)(2)(3)...(n-1)(n). 4
 9, 33, 333, 9999, 33333, 333333, 9999999, 11111111, 111111111, 99999999999, 3333333333333, 333333333333333, 99999999999999999, 3333333333333333333, 333333333333333333333, 99999999999999999999999 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Numerators in A172496. LINKS Table of n, a(n) for n=1..16. EXAMPLE a(10) = 99999999999; 12345678910 / 99999999999 = 0.1234567891012345678910... (period 12345678910). PROG (Sage) def A172498(n): s = ''.join(str(i) for i in range(1, n+1)) f = Integer(s) / (10**len(s)-1) return f.denominator() [A172498(i) for i in range(1, 15)] CROSSREFS Cf. A172496 (numerators), A172499, A172505. Sequence in context: A063423 A183939 A145952 * A276284 A275695 A145925 Adjacent sequences: A172495 A172496 A172497 * A172499 A172500 A172501 KEYWORD nonn,base AUTHOR Jaroslav Krizek, Feb 05 2010 EXTENSIONS Edited and extended by D. S. McNeil, Nov 27 2010 STATUS approved

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Last modified September 27 00:17 EDT 2023. Contains 365669 sequences. (Running on oeis4.)