OFFSET
0,2
COMMENTS
In other words, we tile the plane with polyominoes as small as possible, and for any k > 0, two kominoes cannot share an edge.
This sequence is a variant of A368148.
Empirically, the spiral has 4fold 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:
13231
 
3 121 3
   
2 2 12 2
  
3 1213

13231
PROG
(PARI) \\ See Links section.
CROSSREFS
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Dec 17 2023
STATUS
approved