OFFSET
0,2
COMMENTS
In other words, we tile the plane with polyominoes as small as possible, and for any k > 0, two k-ominoes cannot share an edge.
This sequence is a variant of A368148.
Empirically, the spiral has 4-fold rotational symmetry.
LINKS
Rémy Sigrist, Illustration of the central part of the spiral
Rémy Sigrist, Representation of the first 500 shells
Rémy Sigrist, PARI program
EXAMPLE
The spiral begins:
1---3---2---3---1
| |
3 1---2---1 3
| | | |
2 2 1---2 2
| | |
3 1---2---1---3
|
1---3---2---3---1
PROG
(PARI) \\ See Links section.
CROSSREFS
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Dec 17 2023
STATUS
approved