|
%I #15 Dec 05 2020 04:34:41
%S 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,
%T 12,12,12,36,12,12,36,12,12,36,36,36,108,4,4,12,4,4,12,12,12,36,4,4,
%U 12,4,4,12,12,12,36,12,12,36,12,12,36,36,36,108,4,4,12
%N a(n) is the number of squares at distance n from the central square of a Vicsek fractal.
%C For symmetry reasons, a(n) is a multiple of 4 for any n > 0.
%H Rémy Sigrist, <a href="/A337132/b337132.txt">Table of n, a(n) for n = 0..6561</a>
%H Rémy Sigrist, <a href="/A337132/a337132.png">Illustration of initial terms</a>
%H Rémy Sigrist, <a href="/A337132/a337132.gp.txt">PARI program for A337132</a>
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Vicsek_fractal">Vicsek fractal</a>
%F a(n) = 4 iff n belongs to A153775.
%o (PARI) See Links section.
%Y See A337018 for similar sequences.
%Y Cf. A153775.
%K nonn
%O 0,2
%A _Rémy Sigrist_, Nov 21 2020
|
