Number of 2-sided strip polyominoes with n cells and no holes.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =7a(6) =13a(7) =30a(8) =64a(9) =150a(10) =338a(11) =794a(12) =1836a(13) =4313a(14) =10067a(15) =23621a(16) =55313a(17) =129647a(18) =303720a(19) =711078a(20) =1665037a(21) =3894282a(22) =9111343a(23) =21290577a(24) =49770844a(25) =116206114a(26) =271435025a(27) =633298969a(28) =1478178004a(29) =3446626028