A280789 Triangle read by rows: number of topologically distinct sets of N circles with one pair touching, classified according to number of factors.

1, 2, 1, 6, 3, 1, 16, 10, 3, 1, 46, 30, 11, 3, 1, 128, 91, 34, 11, 3, 1, 364, 268, 108, 35, 11, 3, 1, 1029, 790, 327, 112, 35, 11, 3, 1, 2930, 2308, 992, 344, 113, 35, 11, 3, 1, 8344, 6737, 2962, 1055, 348, 113, 35, 11, 3, 1

Offset: 2

Author

N. J. A. Sloane, Jan 20 2017

Keywords

• nonn
• tabl

Examples

			Triangle begins:
1,
2,1,
6,3,1,
16,10,3,1,
46,30,11,3,1,
128,91,34,11,3,1,
364,268,108,35,11,3,1,
1029,790,327,112,35,11,3,1,
...
		

Links

• R. J. Mathar, Topologically Distinct Sets of Non-intersecting Circles in the Plane, arXiv:1603.00077 [math.CO], 2016.

Crossrefs

Row sums give A269800.