Number of simple graphs on n nodes with vertex count > edge count + 1.

Terms

a(0) =0a(1) =1a(2) =2a(3) =4a(4) =8a(5) =18a(6) =40a(7) =100a(8) =256a(9) =705a(10) =2057a(11) =6370a(12) =20803a(13) =71725a(14) =259678a(15) =985244a(16) =3905022a(17) =16124936a(18) =69188809a(19) =307765510a(20) =1416146859a(21) =6727549181a(22) =32938379216a(23) =165942445714a(24) =859020421012