Number of permutations avoiding the patterns {2413,2431,4213,3412,3421,4231,4321,4312}; number of strong sorting class based on 2413.

A111281

Number of permutations avoiding the patterns {2413,2431,4213,3412,3421,4231,4321,4312}; number of strong sorting class based on 2413.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =16a(5) =40a(6) =100a(7) =252a(8) =636a(9) =1604a(10) =4044a(11) =10196a(12) =25708a(13) =64820a(14) =163436a(15) =412084a(16) =1039020a(17) =2619764a(18) =6605420a(19) =16654772a(20) =41993004a(21) =105880308a(22) =266964460a(23) =673118772a(24) =1697188012a(25) =4279255412a(26) =10789627756a(27) =27204748468a(28) =68593500716a(29) =172950260724

External references