Shifts left 2 places under "CGK" (necklace, element, unlabeled) transform.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =2a(6) =4a(7) =7a(8) =11a(9) =21a(10) =36a(11) =72a(12) =131a(13) =250a(14) =479a(15) =924a(16) =1832a(17) =3553a(18) =7039a(19) =13952a(20) =27720a(21) =55482a(22) =111199a(23) =223683a(24) =451416a(25) =912333a(26) =1850179a(27) =3758123a(28) =7652318a(29) =15609910