Triangle of coefficients of polynomials arising in enumeration of periodic sequences.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =2a(8) =3a(9) =1a(10) =1a(11) =2a(12) =5a(13) =3a(14) =1a(15) =1a(16) =3a(17) =13a(18) =18a(19) =7a(20) =1a(21) =1a(22) =3a(23) =20a(24) =50a(25) =43a(26) =9a(27) =1a(28) =1a(29) =4