OFFSET
0,3
EXAMPLE
The board is numbered with the square spiral:
.
10--132--28--133--9 .
| | .
24 3---6---2 25 32
| | | | |
135 7 0---1 141 378
| | | |
23 4---5---19---8 98
| |
11--131--29--91--26---12
.
.
0 + 1 + 2 + 6 = 9 = 3^2;
0 + 6 + 3 + 7 = 16 = 4^2;
0 + 5 + 19 + 1 = 25 = 5^2, and 0 + 5 + 1 + 9 + 1 = 16 = 4^2;
0 + 7 + 4 + 5 = 16 = 4^2;
1 + 141 + 25 + 2 = 169 = 13^2, and 1 + 1 + 4 + 1 + 2 + 5 + 2 = 16 = 4^2;
141 + 378 + 32 + 25 = 576 = 24^2, and 1 + 4 + 1 + 3 + 7 + 8 + 3 + 2 + 2 + 5 = 36 = 6^2;
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Scott R. Shannon and Eric Angelini, May 17 2022
STATUS
approved