Number of homeomorphically irreducible multigraphs (or series-reduced multigraphs or multigraphs without nodes of degree 2) on 4 labeled nodes.

A060534

Number of homeomorphically irreducible multigraphs (or series-reduced multigraphs or multigraphs without nodes of degree 2) on 4 labeled nodes.

Terms

    a(0) =1a(1) =6a(2) =3a(3) =10a(4) =48a(5) =84a(6) =182a(7) =372a(8) =699a(9) =1222a(10) =2007a(11) =3132a(12) =4688a(13) =6780a(14) =9528a(15) =13068a(16) =17553a(17) =23154a(18) =30061a(19) =38484a(20) =48654a(21) =60824a(22) =75270a(23) =92292a(24) =112215a(25) =135390a(26) =162195a(27) =193036a(28) =228348a(29) =268596

External references