Number of fixed points over all unlabeled functions on n nodes.

Terms

a(0) =0a(1) =1a(2) =3a(3) =8a(4) =22a(5) =58a(6) =158a(7) =426a(8) =1170a(9) =3224a(10) =8977a(11) =25105a(12) =70680a(13) =199739a(14) =566842a(15) =1613454a(16) =4605788a(17) =13177776a(18) =37782903a(19) =108522417a(20) =312207970a(21) =899460505a(22) =2594638480a(23) =7493254511a(24) =21663019843a(25) =62687523055a(26) =181561095507a(27) =526275453283