Number of permutations of length n which avoid the patterns 1234 and 1324.
A053617
Number of permutations of length n which avoid the patterns 1234 and 1324.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =22a(5) =90a(6) =396a(7) =1837a(8) =8864a(9) =44074a(10) =224352a(11) =1163724a(12) =6129840a(13) =32703074a(14) =176351644a(15) =959658200a(16) =5262988330a(17) =29057961666a(18) =161374413196a(19) =900792925199
External references
- oeis: A053617