Place n equally spaced points on each side of an equilateral triangle, and join each of these points by a chord to the 2*n new points on the other two sides: sequence gives number of edges in the resulting planar graph.

A366485

Place n equally spaced points on each side of an equilateral triangle, and join each of these points by a chord to the 2*n new points on the other two sides: sequence gives number of edges in the resulting planar graph.

Terms

    a(0) =3a(1) =9a(2) =48a(3) =237a(4) =684a(5) =1962a(6) =3630a(7) =7617a(8) =12654a(9) =21114a(10) =31170a(11) =50280a(12) =66687a(13) =99342a(14) =132756a(15) =174567a(16) =222495a(17) =302553a(18) =367158a(19) =479226a(20) =579057a(21) =705432a(22) =846477a(23) =1055679a(24) =1217541a(25) =1460205a(26) =1715088a(27) =2011161a(28) =2289753a(29) =2729301

External references