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 A049620 #7 Dec 16 2019 22:09:51
%S A049620 0,0,3,6,11,14,23,26,35,42,55,58,75,78,95,110,127,130,155,158,183,202,
%T A049620 227,230,263,274,303,322,355,358,403,406,439,466,503,526,575,578,619,
%U A049620 650,699,702,763,766,815,858,907,910,975,990,1051,1090,1147,1150,1223,1254,1319,1362,1423,1426,1515,1518,1583
%N A049620 a(n) = T(n,n), array T as in A049615.
%H A049620 G. C. Greubel, <a href="/A049620/b049620.txt">Table of n, a(n) for n = 0..1000</a>
%t A049620 T[n_, k_]:= Length[Select[Flatten[Table[{x, y}, {x,0,n}, {y,0,k}], 1], GCD @@ # > 1 &]]; Table[T[n, n], {n,0,65}] (* _G. C. Greubel_, Dec 16 2019 *)
%Y A049620 Cf. A049615, A049616, A049617, A049618, A049619, A049621, A049622, A049623.
%K A049620 nonn
%O A049620 0,3
%A A049620 _Clark Kimberling_
%E A049620 Terms a(38) onward added by _G. C. Greubel_, Dec 16 2019