Number of permutations of {1,2,...,n} with all odd entries preceding all even entries or all even entries preceding all odd entries.
A152875
Number of permutations of {1,2,...,n} with all odd entries preceding all even entries or all even entries preceding all odd entries.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =4a(4) =8a(5) =24a(6) =72a(7) =288a(8) =1152a(9) =5760a(10) =28800a(11) =172800a(12) =1036800a(13) =7257600a(14) =50803200a(15) =406425600a(16) =3251404800a(17) =29262643200a(18) =263363788800
External references
- oeis: A152875