Number of permutations of length n which avoid the patterns 1342, 3142, 4312; or avoid the patterns 3124, 3412, 3421.

A116823

Number of permutations of length n which avoid the patterns 1342, 3142, 4312; or avoid the patterns 3124, 3412, 3421.

Terms

    a(0) =1a(1) =2a(2) =6a(3) =21a(4) =75a(5) =266a(6) =935a(7) =3263a(8) =11326a(9) =39155a(10) =134955a(11) =464094a(12) =1593231a(13) =5462447a(14) =18709694a(15) =64035275a(16) =219039523a(17) =748919582a(18) =2559777591a(19) =8746974087a(20) =29883271518a(21) =102078226067a(22) =348648695387

External references