

A171928


Numbers k which divide the periodic part of the decimal expansion of 1/k.


3




OFFSET

1,1


COMMENTS

There are two definitions of the periodic part: zeros may either begin or end the periodic part. For example, for 1/11 = 0.0909090..., the periodic part could be either 09 or 90. This sequence assumes that the zeros are at the beginning of the periodic part. See A179267 for the case of zeros at the end of the periodic part. The prime numbers in this sequence are in A045616. The three numbers following 487 are 3*487, 9*487, and 27*487. There are no other multiples of 487 here because 3 and 487 are the only prime factors of 10^4861 that occur to a power greater than 1.  T. D. Noe, Jul 06 2010


LINKS

Table of n, a(n) for n=1..8.
Helmut Richter, Factors of 10^4861


EXAMPLE

6 is a term because 1/6 = 0.166666... has periodic part 6, which is divisible by 6.


CROSSREFS

Cf. A045616, A179267.
Sequence in context: A126297 A157540 A179267 * A308259 A034879 A113588
Adjacent sequences: A171925 A171926 A171927 * A171929 A171930 A171931


KEYWORD

nonn,base,more


AUTHOR

Zhining Yang, Jan 05 2010


EXTENSIONS

Example shortened by T. D. Noe, Jun 27 2010
Extended by T. D. Noe, Jul 06 2010


STATUS

approved



