Number of secondary structures of size n having no stacks of even length.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =7a(6) =14a(7) =31a(8) =66a(9) =141a(10) =313a(11) =702a(12) =1577a(13) =3581a(14) =8207a(15) =18903a(16) =43770a(17) =101903a(18) =238282a(19) =559322a(20) =1317717a(21) =3114676a(22) =7383914a(23) =17552857a(24) =41831618a(25) =99923471a(26) =239200459a(27) =573750288a(28) =1378763083a(29) =3319005743