OFFSET
0,4
COMMENTS
Spiral begins (0 at the center):
.
42--43--44--45--46--47--48
|
41 20--21--22--23--24--25
| | |
40 19 6---7---8---9 26
| | | | |
39 18 5 0---1 10 27
| | | | | |
38 17 4---3---2 11 28
| | | |
37 16--15--14--13--12 29
| |
36--35--34--33--32--31--30
FORMULA
T(n,n) = 0, T(n+1,n) = 1, T(n+2,n) = 2, T(n,k) <= n-k.
EXAMPLE
Triangle begins, 0 <= k <= n:
0
1, 0
2, 1, 0
1, 2, 1, 0
2, 3, 2, 1, 0
1, 2, 3, 2, 1, 0
2, 3, 4, 3, 2, 1, 0
1, 2, 3, 2, 3, 2, 1, 0
2, 1, 2, 3, 4, 3, 2, 1, 0
3, 2, 3, 4, 5, 4, 3, 2, 1, 0
2, 1, 2, 3, 4, 3, 4, 3, 2, 1, 0
3, 2, 1, 2, 3, 4, 5, 4, 3, 2, 1, 0
4, 3, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1, 0
3, 2, 1, 2, 3, 4, 5, 4, 3, 4, 3, 2, 1, 0
2, 3, 2, 1, 2, 3, 4, 3, 4, 5, 4, 3, 2, 1, 0
3, 4, 3, 2, 1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1, 0
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Philippe Deléham, Mar 11 2013
STATUS
approved