login
A334752
a(n) is the number immediately below n in a clockwise square spiral of the positive integers with the first step to the right.
5
4, 3, 14, 15, 16, 5, 6, 1, 2, 11, 12, 13, 32, 33, 34, 35, 36, 17, 18, 19, 20, 7, 8, 9, 10, 27, 28, 29, 30, 31, 58, 59, 60, 61, 62, 63, 64, 37, 38, 39, 40, 41, 42, 21, 22, 23, 24, 25, 26, 51, 52, 53, 54, 55, 56, 57, 92, 93, 94, 95, 96, 97, 98, 99, 100, 65, 66
OFFSET
1,1
COMMENTS
Equivalently the number immediately above n in a counterclockwise square spiral of the positive integers with the first step to the right.
This is a permutation of the positive integers. A334751 is the inverse permutation.
EXAMPLE
For n = 1, a(1) = 4 because 4 is immediately below 1 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), A334751 (above).
Cf. A174344 (x-coordinate), A268038 (y-coordinate).
Sequence in context: A056479 A056480 A284841 * A197883 A222195 A292413
KEYWORD
nonn
AUTHOR
Peter Kagey, May 10 2020
STATUS
approved