A000840 Number of cubic bicolored graphs on n unlabeled nodes admitting an automorphism exchanging the colors.

0, 0, 1, 1, 2, 5, 12, 31, 90, 285, 938, 3285, 11983, 45390, 177803, 718390, 2986407, 12749364, 55802982, 250068732, 1145923828, 5363795830, 25620207380, 124767647097, 618983876918, 3126035142910, 16060182735947, 83883575376862, 445164927249466, 2399098651337048

Offset: 1

Author

Brendan McKay and Eric Rogoyski

Keywords

• nonn

Crossrefs

Column k=3 of A333159.

Cf. A000512, A000843, A004066, A008325.

Extensions

a(11)-a(30) from Andrew Howroyd, Mar 10 2020