Number of permutations of length n which avoid the patterns 1234, 1324, 1432.

A116821

Number of permutations of length n which avoid the patterns 1234, 1324, 1432.

Terms

    a(0) =1a(1) =2a(2) =6a(3) =21a(4) =76a(5) =278a(6) =1019a(7) =3734a(8) =13678a(9) =50100a(10) =183514a(11) =672230a(12) =2462490a(13) =9020556a(14) =33043996a(15) =121046420a(16) =443416116a(17) =1624318192a(18) =5950189652a(19) =21796689568a(20) =79845470136a(21) =292489332488

External references