Define the array k(n,x) = number of m such that tau(gcd(n,m)) is x where m runs from 1 to n. Also define h(n,x) = Sum_{d|n : tau(d) = x} d. The sequence contains numbers n such that k(n,x)*x = h(n,x) has at least one solution x.
1, 2, 4, 32, 48, 180, 189, 224, 288, 360, 432, 1280, 1344, 1536, 1600, 4096, 28672
1 seqfan posts
Thu Oct 13 16:01:21 CEST 2011 [seqfan] cototient divisibility in A196736