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A337132
a(n) is the number of squares at distance n from the central square of a Vicsek fractal.
2
1, 4, 4, 4, 12, 4, 4, 12, 4, 4, 12, 12, 12, 36, 4, 4, 12, 4, 4, 12, 12, 12, 36, 4, 4, 12, 4, 4, 12, 12, 12, 36, 12, 12, 36, 12, 12, 36, 36, 36, 108, 4, 4, 12, 4, 4, 12, 12, 12, 36, 4, 4, 12, 4, 4, 12, 12, 12, 36, 12, 12, 36, 12, 12, 36, 36, 36, 108, 4, 4, 12
OFFSET
0,2
COMMENTS
For symmetry reasons, a(n) is a multiple of 4 for any n > 0.
LINKS
FORMULA
a(n) = 4 iff n belongs to A153775.
PROG
(PARI) See Links section.
CROSSREFS
See A337018 for similar sequences.
Cf. A153775.
Sequence in context: A220931 A219578 A219373 * A151906 A151896 A267191
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Nov 21 2020
STATUS
approved