Number of down-up permutations of n+3 starting with n+1.
A006212
Number of down-up permutations of n+3 starting with n+1.
Terms
- a(0) =0a(1) =1a(2) =4a(3) =14a(4) =56a(5) =256a(6) =1324a(7) =7664a(8) =49136a(9) =345856a(10) =2652244a(11) =22014464a(12) =196658216a(13) =1881389056a(14) =19192151164a(15) =207961585664
External references
- oeis: A006212