Number of chord diagrams with n chords; number of pairings on a necklace.
A007769
Number of chord diagrams with n chords; number of pairings on a necklace.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =5a(4) =18a(5) =105a(6) =902a(7) =9749a(8) =127072a(9) =1915951a(10) =32743182a(11) =624999093a(12) =13176573910a(13) =304072048265
External references
- oeis: A007769