Number of reduced words of length n in the Weyl group A_8.

Terms

a(0) =1a(1) =8a(2) =35a(3) =111a(4) =285a(5) =628a(6) =1230a(7) =2191a(8) =3606a(9) =5545a(10) =8031a(11) =11021a(12) =14395a(13) =17957a(14) =21450a(15) =24584a(16) =27073a(17) =28675a(18) =29228a(19) =28675a(20) =27073a(21) =24584a(22) =21450a(23) =17957a(24) =14395a(25) =11021a(26) =8031a(27) =5545a(28) =3606a(29) =2191