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 A307189 #20 Mar 31 2019 17:26:18 %S A307189 1,4,6,12,23,25,27,33,35,38,40,42,44,54,56,58,64,77,79,81,83,85,95,97, %T A307189 103,105,107,109,112,114,128,130,132,134,136,142,144,146,156,163,165, %U A307189 167,169,171,173,175,189,191,201,203,205,207,213,215,234,236,238 %N A307189 Positions of 1's in the square spiral in A275609. %H A307189 Alois P. Heinz, <a href="/A307189/b307189.txt">Table of n, a(n) for n = 1..20000</a> (first 1249 terms from N. J. A. Sloane) %H A307189 Rémy Sigrist, <a href="/A307189/a307189.png">Colored scatterplot of (x,y) such that A275609(x,y) = 1 and -500 <= x <= 500 and -500 <= y <= 500</a> (where the color is function of (x mod 2) + 2 * (y mod 2)) %Y A307189 Cf. A275609, A307188, A307190, A307191, A307192. %K A307189 nonn %O A307189 1,2 %A A307189 _N. J. A. Sloane_, Mar 28 2019