a(n) = Product_{k=1..n} sigma_{n-k}(k), where sigma_m(k) = sum{j|k} j^m.
A108640
a(n) = Product_{k=1..n} sigma_{n-k}(k), where sigma_m(k) = sum{j|k} j^m.
Terms
- a(0) =1a(1) =2a(2) =6a(3) =60a(4) =1260a(5) =239904a(6) =123263712a(7) =872883648000
External references
- oeis: A108640