Number of 1-sided strip polycairos with n cells.

Terms

a(0) =1a(1) =3a(2) =7a(3) =19a(4) =47a(5) =125a(6) =310a(7) =803a(8) =2020a(9) =5144a(10) =12986a(11) =32829a(12) =82728a(13) =208461a(14) =524092a(15) =1317284a(16) =3305350a(17) =8291010a(18) =20770830