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

A000840

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

Terms

    a(0) =0a(1) =0a(2) =1a(3) =1a(4) =2a(5) =5a(6) =12a(7) =31a(8) =90a(9) =285a(10) =938a(11) =3285a(12) =11983a(13) =45390a(14) =177803a(15) =718390a(16) =2986407a(17) =12749364a(18) =55802982a(19) =250068732a(20) =1145923828a(21) =5363795830a(22) =25620207380a(23) =124767647097a(24) =618983876918

External references