Number of 321-avoiding permutations of length n whose squares also avoid the pattern 321.

A326761

Number of 321-avoiding permutations of length n whose squares also avoid the pattern 321.

Terms

    a(0) =1a(1) =2a(2) =5a(3) =12a(4) =28a(5) =70a(6) =171a(7) =428a(8) =1062a(9) =2664a(10) =6664a(11) =16744a(12) =42018a(13) =105798a(14) =266011a(15) =670140a(16) =1687908a(17) =4253890a(18) =10721040a(19) =27035624a(20) =68164196a(21) =171925882

External references