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A308094
Arrange distinct numbers in a single square spiral so that the absolute difference between each number and its eight neighbors is unique.
0
1, 2, 4, 8, 13, 21, 10, 31, 17, 34, 52, 26, 45, 68, 41, 66, 97, 131, 57, 96, 50, 139, 69, 114, 165, 83, 219, 107, 168, 102, 158, 221, 136, 198, 265, 166, 3, 237, 309, 386, 183, 261, 140, 349, 240, 319, 411, 270, 363, 179, 461, 322, 426, 279, 381, 488, 6, 364
OFFSET
1,2
COMMENTS
Start with 1; always choose smallest number which has not yet appeared.
EXAMPLE
The spiral begins:
.
673--476--896--714--200--610--848--660--181--831--180
| |
877 125--280--513--393----9--336--481--364----6 658
| | | |
1085 429 3--166--265--198--136--221--158 488 187
| | | | | |
770 554 237 97---66---41---68---45 102 381 647
| | | | | | | |
232 7 309 131 13----8----4 26 168 279 18
| | | | | | | | | |
743 523 386 57 21 1----2 52 107 426 584
| | | | | | | | |
964 14 183 96 10---31---17---34 219 322 12
| | | | | | |
1182 405 261 50--139---69--114--165---83 461 842
| | | | |
765 539 140--349--240--319--411--270--363--179 680
| | |
233 5--685--499---11--572---16--565---19--514---15
CROSSREFS
Sequence in context: A130840 A115266 A164508 * A292774 A026039 A004978
KEYWORD
nonn
AUTHOR
Luca Petrone, May 12 2019
STATUS
approved