Number of step cyclic shifted sequence structures using exactly two different symbols.

Terms

a(0) =0a(1) =1a(2) =1a(3) =3a(4) =2a(5) =7a(6) =4a(7) =13a(8) =10a(9) =25a(10) =14a(11) =87a(12) =36a(13) =129a(14) =183a(15) =356a(16) =260a(17) =1345a(18) =804a(19) =3759a(20) =4433a(21) =9757a(22) =8384a(23) =47461a(24) =33780a(25) =108329a(26) =138766a(27) =408375a(28) =331184a(29) =2251815