Number of permutations avoiding the patterns {2413,4213,2431,4231,4321}; also number of permutations avoiding the patterns {3142,3412,3421,4312,4321}; number of weak sorting class based on 2413 or 3142.
A111277
Number of permutations avoiding the patterns {2413,4213,2431,4231,4321}; also number of permutations avoiding the patterns {3142,3412,3421,4312,4321}; number of weak sorting class based on 2413 or 3142.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =19a(5) =59a(6) =180a(7) =544a(8) =1637a(9) =4917a(10) =14758a(11) =44282a(12) =132855a(13) =398575a(14) =1195736a(15) =3587220a(16) =10761673a(17) =32285033a(18) =96855114a(19) =290565358a(20) =871696091a(21) =2615088291a(22) =7845264892a(23) =23535794696a(24) =70607384109a(25) =211822152349a(26) =635466457070
External references
- oeis: A111277