An upper bound for linearized chord diagrams.

Terms

a(0) =1a(1) =2a(2) =4a(3) =10a(4) =28a(5) =100a(6) =421a(7) =2101a(8) =11953a(9) =76121a(10) =533780a(11) =4077565a(12) =33655662a(13) =298278708a(14) =2824175781a(15) =28446451346a(16) =303704165521