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 A307287 #16 Oct 27 2019 11:16:23 %S A307287 0,1,9,13,19,22,37,52,58,69,78,84,90,101,112,118,132,138,149,160,171, %T A307287 180,191,200,211,222,228,237,248,259,268,279,288,299,308,319,325,336, %U A307287 345,356,362,373,382,393,402,413,424,430,441,450,461,470,481,487,498 %N A307287 Coordinates Y_lower(n) of P-positions in Maharaja Nim on square spiral (see Comments for precise definition). %C A307287 We study Maharaja Nim on the square spiral, as in A307282, A307283, and in particular the P-positions in the 4th quadrant. As in A140100 and A140101 (which are the analogs if we use a Queen instead of a Maharaja) we take the X-axis to point South and the Y-axis to point East. %C A307287 The P-positions now lie on two roughly straight lines, with coordinates (X_upper(n), Y_upper(n)) with X_upper(n) <= Y_upper(n), and (X_lower(n), Y_lower(n)) with X_lower(n) <= Y_lower(n). These four sequences are A307284-A307287. %C A307287 The two lines are the hard-to-see black pixels in the fourth quadrant in the Sigrist illustration. %H A307287 Rémy Sigrist, <a href="/A307287/b307287.txt">Table of n, a(n) for n = 0..58</a> %H A307287 Rémy Sigrist, <a href="/A307282/a307282_1.png">Colored representation of the spiral for x = -500..500 and y = -500..500</a> (where the hue is function of T(x,y) and black pixels correspond to 0's) %Y A307287 Cf. A140100, A140101, A307282, A307283, A307284-A307287. %K A307287 nonn %O A307287 0,3 %A A307287 _N. J. A. Sloane_, Apr 08 2019 %E A307287 More terms from _Rémy Sigrist_, Apr 09 2019