Number of permutations of length n which avoid the patterns 1234, 1243, 3214.
A116781
Number of permutations of length n which avoid the patterns 1234, 1243, 3214.
Terms
- a(0) =1a(1) =2a(2) =6a(3) =21a(4) =73a(5) =250a(6) =861a(7) =2967a(8) =10220a(9) =35203a(10) =121263a(11) =417710a(12) =1438865a(13) =4956391a(14) =17073052a(15) =58810751a(16) =202582667a(17) =697827126a(18) =2403772765a(19) =8280164651a(20) =28522299468a(21) =98249443251a(22) =338435304271
External references
- oeis: A116781