A257489 - OEIS

%I #9 Apr 26 2015 14:51:32

%S 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 16,49,59,55,21,61,65,67,22,71,73,6,77,79,39,83,89,12,91,85,57,97,101,

%U 33,35,103,107,18,109,113,32,45,121,119,81,95,127,131,115,133

%N Arrange numbers in a single clockwise spiral so that each number is relatively prime to its 12 nearest neighbors.

%C In the illustration of initial terms (see Links), the 12 nearest neighbors of the first term are highlighted in yellow.

%H Jon E. Schoenfield, <a href="/A257489/b257489.txt">Table of n, a(n) for n = 1..50000</a>

%H Jon E. Schoenfield, <a href="/A257489/a257489_1.png">Illustration of initial terms</a>

%H Jon E. Schoenfield, <a href="/A257489/a257489_2.png">Graph of first 50000 terms</a>

%Y Cf. A064413, A257321-A257340.

%K nonn

%O 1,2

%A _Jon E. Schoenfield_, Apr 26 2015