Number of permutations of length n whose powers all avoid the pattern 321.

A326760

Number of permutations of length n whose powers all avoid the pattern 321.

Terms

    a(0) =1a(1) =2a(2) =5a(3) =12a(4) =28a(5) =70a(6) =161a(7) =386a(8) =932a(9) =2226a(10) =5254a(11) =12748a(12) =30228a(13) =72192a(14) =173415a(15) =414240a(16) =988208a(17) =2369916a(18) =5659160a(19) =13534274a(20) =32394570a(21) =77449544

External references