Invertible triangle: T(n,k) = number of k-ary Lyndon words of length n-k+1 with trace 1 modulo k.

Terms

a(0) =1a(1) =0a(2) =1a(3) =0a(4) =1a(5) =1a(6) =0a(7) =1a(8) =1a(9) =1a(10) =0a(11) =2a(12) =3a(13) =2a(14) =1a(15) =0a(16) =3a(17) =6a(18) =5a(19) =2a(20) =1a(21) =0a(22) =5a(23) =16a(24) =16a(25) =8a(26) =3a(27) =1a(28) =0a(29) =9