Number of cubic graphs on n unlabeled nodes with half-edges.

Terms

a(0) =1a(1) =0a(2) =0a(3) =1a(4) =3a(5) =4a(6) =12a(7) =24a(8) =70a(9) =172a(10) =525a(11) =1530a(12) =5078a(13) =16994a(14) =61456a(15) =228898a(16) =895910a(17) =3617148a(18) =15130833a(19) =65084088a(20) =287828488a(21) =1304327221a(22) =6050218591a(23) =28675928883a(24) =138730847262a(25) =684300453848