Number of unlabeled nonseparable (or 2-connected) loopless multigraphs with n edges.

A010357

Number of unlabeled nonseparable (or 2-connected) loopless multigraphs with n edges.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =3a(4) =6a(5) =14a(6) =32a(7) =90a(8) =279a(9) =942a(10) =3468a(11) =13777a(12) =57747a(13) =254671a(14) =1170565a(15) =5580706a(16) =27487418a(17) =139477796a(18) =727458338a(19) =3893078684a(20) =21346838204a(21) =119787629215a(22) =687200870250

External references