Number of prime knots with <= n crossings.

Terms

a(0) =0a(1) =0a(2) =1a(3) =2a(4) =4a(5) =7a(6) =14a(7) =35a(8) =84a(9) =249a(10) =801a(11) =2977a(12) =12965a(13) =59937a(14) =313230a(15) =1701935a(16) =9755328a(17) =58021794a(18) =352152252