a(n) = n!*Sum_{m=0..floor(n/2)} binomial(n,2*m)^(-1).
A358791
a(n) = n!*Sum_{m=0..floor(n/2)} binomial(n,2*m)^(-1).
Terms
- a(0) =1a(1) =1a(2) =4a(3) =8a(4) =52a(5) =156a(6) =1536a(7) =6144a(8) =84096a(9) =420480a(10) =7453440a(11) =44720640a(12) =974972160a(13) =6824805120a(14) =176504832000
External references
- oeis: A358791