a(n) = (1/n)*Sum_{d|n} moebius(d)*2^(n^2/d).
A168649
a(n) = (1/n)*Sum_{d|n} moebius(d)*2^(n^2/d).
Terms
- a(0) =2a(1) =6a(2) =168a(3) =16320a(4) =6710880a(5) =11453201760
External references
- oeis: A168649
A168649
a(n) = (1/n)*Sum_{d|n} moebius(d)*2^(n^2/d).