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 A049646 #16 Dec 08 2017 20:57:49
%S A049646 0,1,3,4,5,7,9,11,13,17,21,23,25,31,37,41,45,51,57,61,65,75,85,89,93,
%T A049646 105,117,123,129,137,145,153,161,177,193,199,205,223,241,249,257,269,
%U A049646 281,291,301,323,345,353,361,381,401,413,425,443,461,473,485,513,541,549,557
%N A049646 a(n) = T(n,n+1), array T given by A049639.
%H A049646 G. C. Greubel, <a href="/A049646/b049646.txt">Table of n, a(n) for n = 0..75</a>
%t A049646 a[0 | 1, 0 | 1] = 0; a[0 | 1, _] = a[_, 0 | 1] = 1; a[i_, j_] := Module[{slopes, cnt}, slopes = Union@Flatten@Table[(k - j)/(h - i), {h, 0, i - 1}, {k, 0, j - 1}]; cnt[slope_] := Count[Flatten[Table[{h, k}, {h, 0, i - 1}, {k, 0, j - 1}], 1], {h_, k_} /; (k - j)/(h - i) == slope]; Count[cnt /@ slopes, c_ /; c >= 2] + 2]; Table[a[n, n + 1], {n, 0, 25}] (* _G. C. Greubel_, Dec 07 2017 *)
%Y A049646 Cf. A049639.
%K A049646 nonn
%O A049646 0,3
%A A049646 _Clark Kimberling_
%E A049646 Terms a(39)-a(60) added by _G. C. Greubel_, Dec 07 2017