Members of
A111434 not congruent to 0 (mod 10). If k is a member of
A111434 then so is 10^e*k.
The authors have calculated all members below 10^11.
The number of members less than 10^n {n=0..11}: 0,1,1,3,5,7,7,7,16,34,57,125.
Number of members congruent to k (mod 10): 0,7,1,0,2,23,8,20,49,15. But more interesting, number of members are congruent to k (mod 9): 66,59,0,0,0,0,0,0,0.
A007953(n) == n mod 9. Since 0 and 1 are the only k in [0,1,...8] with k == k^2 mod 9, all terms are congruent to 0 or 1 mod 9. -
Robert Israel, Jan 26 2015
