a(n) = n! * Sum_{k=0..floor((n-1)/4)} 1 / (4*k+1)!.
A349089
a(n) = n! * Sum_{k=0..floor((n-1)/4)} 1 / (4*k+1)!.
Terms
- a(0) =0a(1) =1a(2) =2a(3) =6a(4) =24a(5) =121a(6) =726a(7) =5082a(8) =40656a(9) =365905a(10) =3659050a(11) =40249550a(12) =482994600a(13) =6278929801a(14) =87905017214
External references
- oeis: A349089