Number of commutative elements in Coxeter group F_n.

Terms

a(0) =24a(1) =106a(2) =464a(3) =2003a(4) =8560a(5) =36333a(6) =153584a(7) =647775a(8) =2729365a(9) =11496788a(10) =48433965a(11) =204115805a(12) =860593940a(13) =3630164290a(14) =15319869152a(15) =64680076487a(16) =273183844396