Number of symmetric bargraphs having semiperimeter n (n>=2).

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =9a(5) =15a(6) =27a(7) =46a(8) =83a(9) =143a(10) =259a(11) =450a(12) =817a(13) =1429a(14) =2599a(15) =4570a(16) =8323a(17) =14698a(18) =26797a(19) =47491a(20) =86659a(21) =154042a(22) =281287a(23) =501283a(24) =915907a(25) =1635835a(26) =2990383a(27) =5351138a(28) =9786369a(29) =17541671