Number of homeomorphically irreducible multigraphs (or series-reduced multigraphs or multigraphs without nodes of degree 2) on 6 labeled nodes.

A060536

Number of homeomorphically irreducible multigraphs (or series-reduced multigraphs or multigraphs without nodes of degree 2) on 6 labeled nodes.

Terms

    a(0) =1a(1) =15a(2) =45a(3) =90a(4) =495a(5) =1866a(6) =5990a(7) =19920a(8) =62655a(9) =186525a(10) =526470a(11) =1403265a(12) =3530000a(13) =8388495a(14) =18884475a(15) =40442635a(16) =82775970a(17) =162663240a(18) =308201500a(19) =565176105a(20) =1006419120a(21) =1745321275a(22) =2955037455a(23) =4895398755a(24) =7950135835a(25) =12677752431

External references