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 A306608 #11 Apr 11 2019 07:24:59 %S A306608 1,2,2,2,3,2,3,4,4,3,3,5,4,5,3,4,5,6,6,5,4,4,6,6,7,6,6,4,4,6,7,8,8,7, %T A306608 6,4,4,7,8,9,8,9,8,7,4,5,7,8,9,10,10,9,8,7,5,5,8,8,10,10,11,10,10,8,8, %U A306608 5,5,8,10,11,11,12,12,11,11,10,8,5 %N A306608 Table read by antidiagonals: T(x,y) is the minimum size of a planar additive basis for the rectangle [0,x]*[0,y], for x,y >= 0. %C A306608 A planar additive basis is a set of points with nonnegative integer coordinates such that their pairwise sums cover a given rectangle of points with integer coordinates. Pairwise sums of a point with itself are included. %C A306608 T(x,y) = T(y,x). %H A306608 J. Kohonen, V. Koivunen and R. Rajamäki, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL21/Rajamaki/raj.html">Planar additive bases for rectangles</a>, Journal of Integer Sequences, 21 (2018), Article 18.9.8. [see Table 2] %e A306608 The table starts: %e A306608 1, 2, 2, 3, 3, 4, 4, ... %e A306608 2, 3, 4, 5, 5, 6, ... %e A306608 2, 4, 4, 6, 6, ... %e A306608 3, 5, 6, 7, ... %e A306608 3, 5, 6, ... %e A306608 4, 6, ... %e A306608 4, ... %e A306608 ... %e A306608 T(6,3)=9: The rectangle [0,6]*[0,3] has the following minimum basis of 9 elements, with elements marked as "*", and empty locations as "-". %e A306608 3 *------ %e A306608 2 ---*--- %e A306608 1 **-*--- %e A306608 0 ***--*- %e A306608 0123456 %Y A306608 Main diagonal is A295771. %K A306608 nonn,tabl %O A306608 0,2 %A A306608 _Jukka Kohonen_, Feb 28 2019