OFFSET
0,2
COMMENTS
For symmetry reasons, a(n) is a multiple of 4 for any n > 0.
LINKS
Rémy Sigrist, Table of n, a(n) for n = 0..6561
Rémy Sigrist, Illustration of initial terms
Rémy Sigrist, PARI program for A337132
Wikipedia, Vicsek fractal
FORMULA
a(n) = 4 iff n belongs to A153775.
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Nov 21 2020
STATUS
approved