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 A257489 #9 Apr 26 2015 14:51:32 %S A257489 1,2,3,5,4,7,9,11,13,15,17,19,8,23,29,27,25,31,37,10,41,43,14,47,53, %T A257489 16,49,59,55,21,61,65,67,22,71,73,6,77,79,39,83,89,12,91,85,57,97,101, %U A257489 33,35,103,107,18,109,113,32,45,121,119,81,95,127,131,115,133 %N A257489 Arrange numbers in a single clockwise spiral so that each number is relatively prime to its 12 nearest neighbors. %C A257489 In the illustration of initial terms (see Links), the 12 nearest neighbors of the first term are highlighted in yellow. %H A257489 Jon E. Schoenfield, <a href="/A257489/b257489.txt">Table of n, a(n) for n = 1..50000</a> %H A257489 Jon E. Schoenfield, <a href="/A257489/a257489_1.png">Illustration of initial terms</a> %H A257489 Jon E. Schoenfield, <a href="/A257489/a257489_2.png">Graph of first 50000 terms</a> %Y A257489 Cf. A064413, A257321-A257340. %K A257489 nonn %O A257489 1,2 %A A257489 _Jon E. Schoenfield_, Apr 26 2015