Numbers n where n^2 divides A159553(n), where A159553(n) = sum{k=0 to n} binomial(n,k) * GCD(n,k).
1, 6, 22, 72, 114, 148, 164, 260, 261, 780, 1078, 1184, 1266, 2952, 467
2 seqfan posts
Tue Apr 14 23:04:24 CEST 2009 [seqfan] Re: When n^2 divides sum