Number of unrooted two-vertex (or, dually, two-face) regular planar maps of even valency 2n considered up to orientation-preserving homeomorphism.

A113181

Number of unrooted two-vertex (or, dually, two-face) regular planar maps of even valency 2n considered up to orientation-preserving homeomorphism.

Terms

    a(0) =1a(1) =3a(2) =14a(3) =95a(4) =859a(5) =9130a(6) =106039a(7) =1297295a(8) =16428300a(9) =213388961a(10) =2827645453a(11) =38086408002a(12) =520062618300

External references