Number of permutations of [n] starting and ending with an odd number.
A199495
Number of permutations of [n] starting and ending with an odd number.
Terms
- a(0) =0a(1) =1a(2) =0a(3) =2a(4) =4a(5) =36a(6) =144a(7) =1440a(8) =8640a(9) =100800a(10) =806400a(11) =10886400a(12) =108864000a(13) =1676505600a(14) =20118067200a(15) =348713164800
External references
- oeis: A199495