Number of permutations of length n which avoid the patterns 1243 and 2341.

A165536

Number of permutations of length n which avoid the patterns 1243 and 2341.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =22a(5) =88a(6) =365a(7) =1540a(8) =6568a(9) =28269a(10) =122752a(11) =537708a(12) =2375500a(13) =10579400a(14) =47469377a(15) =214454528a(16) =974870969a(17) =4456401809a(18) =20474068387a(19) =94490731125a(20) =437872264778

External references