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A334751
a(n) is the number immediately above n in a clockwise square spiral of the positive integers with the first step to the right.
5
8, 9, 2, 1, 6, 7, 22, 23, 24, 25, 10, 11, 12, 3, 4, 5, 18, 19, 20, 21, 44, 45, 46, 47, 48, 49, 26, 27, 28, 29, 30, 13, 14, 15, 16, 17, 38, 39, 40, 41, 42, 43, 74, 75, 76, 77, 78, 79, 80, 81, 50, 51, 52, 53, 54, 55, 56, 31, 32, 33, 34, 35, 36, 37, 66, 67, 68, 69
OFFSET
1,1
COMMENTS
Equivalently the number immediately below n in a counterclockwise spiral of the positive integers with the first step to the right.
This is a permutation of the positive integers. A334752 is the inverse permutation.
EXAMPLE
For n = 1, a(1) = 8 because 8 is immediately above one in the clockwise square spiral with first step to the right:
21--22--23--24--25--26
| |
20 7---8---9---10 27
| | | |
19 6 1---2 11 28
| | | | |
18 5---4---3 12 29
| | |
17--16--15--14--13 30
|
36--35--34--33--32--31
CROSSREFS
Cf. A068225 (right), A068226 (left), A334752 (below).
Cf. A174344 (x-coordinate), A268038 (y-coordinate).
Sequence in context: A297537 A030167 A010767 * A289252 A064734 A090929
KEYWORD
nonn
AUTHOR
Peter Kagey, May 10 2020
STATUS
approved