Number of permutations avoiding the patterns {3241,3421,4321}; number of weak sorting class based on 3241.

A111279

Number of permutations avoiding the patterns {3241,3421,4321}; number of weak sorting class based on 3241.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =21a(5) =79a(6) =309a(7) =1237a(8) =5026a(9) =20626a(10) =85242a(11) =354080a(12) =1476368a(13) =6173634a(14) =25873744a(15) =108628550a(16) =456710589a(17) =1922354351a(18) =8098984433a(19) =34147706833a(20) =144068881455a(21) =608151037123

External references