Bilateral directed animals in first and 8th octants.

Terms

a(0) =1a(1) =1a(2) =3a(3) =8a(4) =23a(5) =67a(6) =198a(7) =590a(8) =1769a(9) =5328a(10) =16103a(11) =48801a(12) =148216a(13) =450952a(14) =1374044a(15) =4191814a(16) =12801243a(17) =39127766a(18) =119687036a(19) =366348367a(20) =1121992447a(21) =3437981365a(22) =10539237135a(23) =32321011234a(24) =99154404456a(25) =304280556111a(26) =934022848612