OFFSET
1,2
COMMENTS
Start by creating a grid of integers starting with 1 in the center and spiraling outward.
.
64--63--62--61--60--59--58--57
|
37--36--35--34--33--32--31 56
| | |
38 17--16--15--14--13 30 55
| | | | |
39 18 5---4---3 12 29 54
| | | | | | |
40 19 6 1---2 11 28 53
| | | | | |
41 20 7---8---9--10 27 52
| | | |
42 21--22--23--24--25--26 51
| |
43--44--45--46--47--48--49--50
.
Then starting with 1 mark all numbers that have no neighboring marked numbers.
.
. 64 __ 62 __ 60 __ __ __
.
. __ __ __ __ __ __ 31 __
.
. __ 17 __ 15 __ __ __ __
.
. __ __ __ __ __ 12 __ 54
.
. __ 19 __ 1 __ __ __ __
.
. __ __ __ __ __ 10 __ 52
.
. __ 21 __ 23 __ __ __ __
.
. __ __ __ __ __ 48 __ 50
LINKS
Michael P. Tilley, Table of n, a(n) for n = 1..10383
Michael P. Tilley, Image of a 204 X 204 grid
CROSSREFS
KEYWORD
nonn
AUTHOR
Michael P. Tilley, Oct 12 2014
STATUS
approved