OFFSET
0,7
COMMENTS
This sequence is a variant of A308896; here we walk a bishop, there a rook.
Visually, we have a superposition of two images that we can separate by considering the parity of the x and y coordinates (see illustrations in Links section).
LINKS
Rémy Sigrist, Table of n, a(n) for n = 0..10200
Rémy Sigrist, Colored representation of the spiral for -512 <= x, y <= 512 and x any y have the same parity
Rémy Sigrist, Colored representation of the spiral for -512 <= x, y <= 512 and x and y have different parity
Rémy Sigrist, PARI program for A337108
FORMULA
a(n) = 0 iff n belongs to A035608.
EXAMPLE
The spiral begins:
7----7----6----7----1----7----4----7----7
| |
6 5----5----4----1----5----5----5 6
| | | |
3 4 3----3----2----3----3 4 3
| | | | | |
6 5 2 1----1----1 2 4 6
| | | | | | | |
0 0 0 0 0----0 0 0 0
| | | | | | |
6 3 2 2----1----2----2 3 6
| | | | |
7 4 4----3----1----3----4----4 5
| | |
6 6----5----5----1----6----5----6----6
|
8----7----8----7----1----7----4----7----8
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Aug 16 2020
STATUS
approved