Number of reduced words of length n in the infinite affine Weyl group (E_6)^{~} on 7 generators.

Terms

a(0) =1a(1) =7a(2) =27a(3) =77a(4) =183a(5) =385a(6) =740a(7) =1325a(8) =2242a(9) =3623a(10) =5633a(11) =8474a(12) =12391a(13) =17676a(14) =24670a(15) =33768a(16) =45426a(17) =60164a(18) =78568a(19) =101296a(20) =129083a(21) =162742a(22) =203168a(23) =251346a(24) =308355a(25) =375369a(26) =453663a(27) =544620a(28) =649732a(29) =770602