Number of permutations of length n which avoid the patterns 4231 and 3214.

A165532

Number of permutations of length n which avoid the patterns 4231 and 3214.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =22a(5) =87a(6) =352a(7) =1428a(8) =5768a(9) =23156a(10) =92416a(11) =367007a(12) =1451780a(13) =5725959a(14) =22535868a(15) =88566290a(16) =347742688a(17) =1364637732a(18) =5353992916a(19) =21005649217a(20) =82425637860a(21) =323523434437

External references