OFFSET
1,4
COMMENTS
For a given a(n)>0, all the values of k such that (10^k+1)=0 mod prime(n)^2 are given by the sequence a(n)*A005408, i.e. odd multiples of a(n). For example, for n=5, prime(5)=11, a(n)=11, the set of values of k for which (10^k+1)=0 mod 11^2 is 11*A005408=11,33,55,77,99,... All the terms of the sequence a(n) are integer multiples of prime(n) for primes <1000 except for a(93)=243 where prime(93)=487.
LINKS
Charles R. Greathouse IV, Sep 10, 2008, Table of n, a(n) for n = 1..4000
EXAMPLE
a(4)=21 since 21 is least value of k for which (10^k+1)=0 mod 7^2.
CROSSREFS
KEYWORD
nonn
AUTHOR
Ray Chandler, Jul 27 2003
STATUS
approved