Number of 1-sided snake polyominoes with n cells.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =10a(5) =24a(6) =53a(7) =126a(8) =289a(9) =686a(10) =1604a(11) =3792a(12) =8925a(13) =21051a(14) =49638a(15) =116858a(16) =275480a(17) =647573a(18) =1525113a(19) =3580673a(20) =8423334a(21) =19755938a(22) =46422915a(23) =108783480a(24) =255359883a(25) =597932342a(26) =1402308318a(27) =3281352516a(28) =7689369625a(29) =17982241557