Number of homeomorphically irreducible multigraphs (or series-reduced multigraphs or multigraphs without nodes of degree 2) on 7 labeled nodes.

A060537

Number of homeomorphically irreducible multigraphs (or series-reduced multigraphs or multigraphs without nodes of degree 2) on 7 labeled nodes.

Terms

    a(0) =1a(1) =21a(2) =105a(3) =266a(4) =1386a(5) =6678a(6) =25403a(7) =100506a(8) =384678a(9) =1393903a(10) =4831890a(11) =15955485a(12) =50080478a(13) =149211930a(14) =421819950a(15) =1132236630a(16) =2890927935a(17) =7040892159a(18) =16411041500a(19) =36733789575a(20) =79230165105a(21) =165194651065a(22) =333926559540

External references