Number of Abelian cubefree words over a 3-letter alphabet.

Terms

a(0) =1a(1) =3a(2) =9a(3) =24a(4) =66a(5) =180a(6) =468a(7) =1206a(8) =3150a(9) =7998a(10) =20124a(11) =50520a(12) =124044a(13) =303906a(14) =744870a(15) =1790226a(16) =4319322a(17) =10432044a(18) =24926934a(19) =59570514a(20) =142662384a(21) =339247320a(22) =807092274a(23) =1920506232a(24) =4543861644