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 A307191 #13 Mar 31 2019 17:27:46 %S A307191 3,7,10,17,19,24,29,32,34,43,45,50,52,57,65,67,69,71,78,80,87,89,94, %T A307191 96,99,111,113,115,122,124,126,133,135,145,148,150,152,154,164,166, %U A307191 168,177,179,181,188,190,193,195,209,212,214,216,226,228,230,232,241 %N A307191 Positions of 3's in the square spiral in A275609. %H A307191 Alois P. Heinz, <a href="/A307191/b307191.txt">Table of n, a(n) for n = 1..20000</a> (first 1216 terms from N. J. A. Sloane) %H A307191 Rémy Sigrist, <a href="/A307191/a307191.png">Colored scatterplot of (x,y) such that A275609(x,y) = 3 and -500 <= x <= 500 and -500 <= y <= 500</a> (where the color is function of (x mod 2) + 2 * (y mod 2)) %Y A307191 Cf. A275609, A307188-A307192. %K A307191 nonn %O A307191 1,1 %A A307191 _N. J. A. Sloane_, Mar 28 2019