a(n) = n! * Sum_{k=1..n} n/floor(n/k)^2.
A345686
a(n) = n! * Sum_{k=1..n} n/floor(n/k)^2.
Terms
- a(0) =1a(1) =5a(2) =38a(3) =222a(4) =1974a(5) =14640a(6) =154580a(7) =1476720a(8) =17753400a(9) =205430400a(10) =2924030592a(11) =38559628800a(12) =623916216000
External references
- oeis: A345686