Square array T(r,m) read by antidiagonals: number of cyclically reduced words of length m in F_r.

Terms

a(0) =2a(1) =4a(2) =2a(3) =6a(4) =12a(5) =2a(6) =8a(7) =30a(8) =28a(9) =2a(10) =10a(11) =56a(12) =126a(13) =84a(14) =2a(15) =12a(16) =90a(17) =344a(18) =630a(19) =244a(20) =2a(21) =14a(22) =132a(23) =730a(24) =2408a(25) =3126a(26) =732a(27) =2a(28) =16a(29) =182