Number of loopless multigraphs with 6 nodes and n edges.

Terms

a(0) =1a(1) =1a(2) =3a(3) =8a(4) =21a(5) =52a(6) =132a(7) =313a(8) =741a(9) =1684a(10) =3711a(11) =7895a(12) =16310a(13) =32604a(14) =63363a(15) =119745a(16) =220546a(17) =396428a(18) =696750a(19) =1198812a(20) =2022503a(21) =3349574a(22) =5452496a(23) =8732932a(24) =13776366a(25) =21423968a(26) =32872642a(27) =49804323a(28) =74560913a(29) =110369469