Number of down-up permutations of n+4 starting with n+1.
A006213
Number of down-up permutations of n+4 starting with n+1.
Terms
- a(0) =0a(1) =2a(2) =10a(3) =46a(4) =224a(5) =1202a(6) =7120a(7) =46366a(8) =329984a(9) =2551202a(10) =21306880a(11) =191252686a(12) =1836652544a(13) =18793429202a(14) =204154071040
External references
- oeis: A006213