Number of isomorphism classes of simple quadrangulations of the sphere having n+2 vertices and n faces, minimal degree 3, with orientation-reversing isomorphisms permitted.

A078666

Number of isomorphism classes of simple quadrangulations of the sphere having n+2 vertices and n faces, minimal degree 3, with orientation-reversing isomorphisms permitted.

Terms

    a(0) =1a(1) =0a(2) =1a(3) =1a(4) =3a(5) =3a(6) =12a(7) =19a(8) =64a(9) =155a(10) =510a(11) =1514a(12) =5146a(13) =16966a(14) =58782a(15) =203269a(16) =716607a(17) =2536201a(18) =9062402a(19) =32533568a(20) =117498072a(21) =426212952a(22) =1553048548a(23) =5681011890a(24) =20858998805a(25) =76850220654a(26) =284057538480

External references