OFFSET
0,3
COMMENTS
This sequence is a two-dimensional variant of A088177.
Visually, we have a superposition of two images that we can separate by considering the parity of the sum of the x and y coordinates (see illustrations in Links section).
LINKS
Rémy Sigrist, Table of n, a(n) for n = 0..10200 (-50 <= x <= 50 and -50 <= y <= 50)
Rémy Sigrist, Colored illustration of the sequence (with cells (x,y) such that -500 <= x <= 500 and -500 <= y <= 500)
Rémy Sigrist, PARI program for A307838
EXAMPLE
The spiral begins:
7---19---16---29---14---22---13---43----3---47----2
| |
31 8---21----7---20---11---17----9---31----1 43
| | | |
2 37 1---23----8---12----7---14----5 19 14
| | | | | |
53 3 29 2---10----5----9----3 11 11 14
| | | | | | | |
4 41 5 13 3----3----2 8 13 9 21
| | | | | | | | | |
37 11 15 7 4 1----1 11 4 25 11
| | | | | | | | |
10 24 8 16 2----5----7----2 19 6 31
| | | | | | |
19 9 22 3---17----5----8---18----3 27 10
| | | | |
12 35 5---23----4---18---17----6---26----5 25
| | |
23 6---34---10---29---13----1---41----7---36----8
|
9---29----8---26---12---25---49----8---32---10---43
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
nonn
AUTHOR
Rémy Sigrist, May 01 2019
STATUS
approved