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 A049644 #10 Dec 11 2017 05:06:19
%S A049644 0,0,3,3,5,5,9,9,13,13,21,21,25,25,37,37,45,45,57,57,65,65,85,85,93,
%T A049644 93,117,117,129,129,145,145,161,161,193,193,205,205,241,241,257,257,
%U A049644 281,281,301,301,345,345,361,361,401,401,425,425,461,461,485,485,541,541,557,557
%N A049644 T(n,n), array T given by A049639.
%H A049644 G. C. Greubel, <a href="/A049644/b049644.txt">Table of n, a(n) for n = 0..75</a>
%t A049644 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], {n, 0, 25}] (* _G. C. Greubel_, Dec 07 2017 *)
%Y A049644 Cf. A049691, A206297.
%K A049644 nonn
%O A049644 0,3
%A A049644 _Clark Kimberling_
%E A049644 Terms a(42) onward added by _G. C. Greubel_, Dec 10 2017