Number of connected categories with n objects and 2n-1 morphisms.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =6a(5) =10a(6) =22a(7) =42a(8) =94a(9) =203a(10) =470a(11) =1082a(12) =2602a(13) =6270a(14) =15482a(15) =38525a(16) =97258a(17) =247448a(18) =635910a(19) =1645411a(20) =4289010a(21) =11245670a(22) =29656148a(23) =78595028a(24) =209273780a(25) =559574414a(26) =1502130920a(27) =4046853091a(28) =10939133170a(29) =29661655793