This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A280789 #9 May 01 2020 07:56:46 %S A280789 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, %T A280789 11,3,1,1029,790,327,112,35,11,3,1,2930,2308,992,344,113,35,11,3,1, %U A280789 8344,6737,2962,1055,348,113,35,11,3,1 %N A280789 Triangle read by rows: number of topologically distinct sets of N circles with one pair touching, classified according to number of factors. %H A280789 R. J. Mathar, <a href="http://arxiv.org/abs/1603.00077">Topologically Distinct Sets of Non-intersecting Circles in the Plane</a>, arXiv:1603.00077 [math.CO], 2016. %e A280789 Triangle begins: %e A280789 1, %e A280789 2,1, %e A280789 6,3,1, %e A280789 16,10,3,1, %e A280789 46,30,11,3,1, %e A280789 128,91,34,11,3,1, %e A280789 364,268,108,35,11,3,1, %e A280789 1029,790,327,112,35,11,3,1, %e A280789 ... %Y A280789 Row sums give A269800. %K A280789 nonn,tabl %O A280789 2,2 %A A280789 _N. J. A. Sloane_, Jan 20 2017