Number of 1-sided triangular strip polyedges with n cells.

Terms

a(0) =1a(1) =3a(2) =14a(3) =54a(4) =239a(5) =1007a(6) =4375a(7) =18728a(8) =80572a(9) =344651a(10) =1473402a(11) =6280556a(12) =26732173a(13) =113570050a(14) =481832209a(15) =2041461824a(16) =8639576140a(17) =36524803606a(18) =154269617690a(19) =651036955831