Number of equal-length matchings of 2n uniformly spaced points on a circle.

Terms

a(0) =1a(1) =3a(2) =3a(3) =9a(4) =5a(5) =17a(6) =7a(7) =33a(8) =15a(9) =49a(10) =11a(11) =113a(12) =13a(13) =153a(14) =57a(15) =321a(16) =17a(17) =617a(18) =19a(19) =1153a(20) =165a(21) =2089a(22) =23a(23) =4577a(24) =85a(25) =8241a(26) =555a(27) =16737a(28) =29a(29) =34049