Number of permutations w in S_n whose Kazhdan-Lusztig polynomial evaluated at q=1 is less than or equal to 2; P_{id,w}(1) <= 2.

A224255

Number of permutations w in S_n whose Kazhdan-Lusztig polynomial evaluated at q=1 is less than or equal to 2; P_{id,w}(1) <= 2.

Terms

    a(0) =1a(1) =2a(2) =6a(3) =24a(4) =115a(5) =590a(6) =3050a(7) =15576a(8) =78318a(9) =388208

External references