Number of polyenes with 2n carbon atoms.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =11a(5) =30a(6) =96a(7) =319a(8) =1135a(9) =4150a(10) =15690a(11) =60506a(12) =237853a(13) =948455a(14) =3831226a(15) =15642947a(16) =64484774a(17) =268055006a(18) =1122646262a(19) =4733357618a(20) =20078203381a(21) =85637471487a(22) =367093826598