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A172503 a(n) = numerator of fraction a/b, where gcd(a, b) = 1, whose decimal representation has the form (n).(n)(n)(n)... with period (n). 2
10, 20, 10, 40, 50, 20, 70, 80, 10, 1000, 100, 400, 1300, 1400, 500, 1600, 1700, 200, 1900, 2000, 700, 200, 2300, 800, 2500, 2600, 300, 2800, 2900, 1000, 3100, 3200, 100, 3400, 3500, 400, 3700, 3800, 1300, 4000, 4100, 1400, 4300, 400, 500, 4600, 4700, 1600, 4900, 5000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Denominators in A172504.

LINKS

David A. Corneth, Table of n, a(n) for n = 1..10000

EXAMPLE

a(10) = 1000; 1000/99 = 10.10101010... (period 10).

a(9) = 10; 10/1 = 9.9999999...

PROG

(PARI) a(n) = qd = #digits(n); numerator(n / (10^(qd)-1)) * 10^qd \\ David A. Corneth, Apr 28 2019

CROSSREFS

Cf. A172504.

Sequence in context: A255529 A023916 A297353 * A107859 A294069 A249585

Adjacent sequences:  A172500 A172501 A172502 * A172504 A172505 A172506

KEYWORD

nonn,frac,easy

AUTHOR

Jaroslav Krizek, Feb 05 2010

EXTENSIONS

More terms from David A. Corneth, Apr 28 2019

STATUS

approved

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Last modified April 20 15:21 EDT 2021. Contains 343135 sequences. (Running on oeis4.)