Number of reduced words of length n in the Weyl group A_19.

Terms

a(0) =1a(1) =19a(2) =189a(3) =1310a(4) =7105a(5) =32110a(6) =125761a(7) =438407a(8) =1386735a(9) =4038090a(10) =10947079a(11) =27876345a(12) =67163518a(13) =154022930a(14) =337879565a(15) =712033264a(16) =1446677555a(17) =2842707951a(18) =5417028610a(19) =10034398370a(20) =18106447251a(21) =31885534341a(22) =54889773721a(23) =92505945904a(24) =152829185554a(25) =247812240270