Number of idempotents in the Kauffman monoid K_n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =5a(5) =15a(6) =31a(7) =93a(8) =215a(9) =653a(10) =1619a(11) =4979a(12) =12949a(13) =40293a(14) =108517a(15) =341241a(16) =943937a(17) =2996127a(18) =8465319a(19) =27092419a(20) =77878271a(21) =251073791a(22) =732129719a(23) =2375764351a(24) =7012025277a(25) =22886955207a(26) =68254122669a(27) =223946197065a(28) =673885100857