An upper bound for linearized chord diagrams.

Terms

a(0) =0a(1) =1a(2) =1a(3) =3a(4) =5a(5) =18a(6) =61a(7) =357a(8) =2330a(9) =18715a(10) =167783a(11) =1686327a(12) =18615873a(13) =224310263a(14) =2926679435a(15) =41112186396a(16) =618573033369