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Coordination sequence for Wilkinson's 123-circle packing with respect to a circle of radius 3.
3

%I #23 Sep 21 2022 02:59:17

%S 1,8,16,28,32,48,48,68,64,88,80,108,96,128,112,148,128,168,144,188,

%T 160,208,176,228,192,248,208,268,224,288,240,308,256,328,272,348,288,

%U 368,304,388,320,408,336,428,352,448,368,468,384,488,400,508,416,528,432

%N Coordination sequence for Wilkinson's 123-circle packing with respect to a circle of radius 3.

%C See A348227 for much more information about this structure.

%H Rémy Sigrist, <a href="/A348231/a348231.gp.txt">PARI program for A348231</a>

%F G.f. = (1 + 8*q + 14*q^2 + 12*q^3 + q^4)/(1 - q^2)^2. [This has not yet been officially proved, but it will follow from the "coloring book" method in the same way that the g.f. for A348227 was established.]

%o (PARI) See Links section.

%Y Cf. A348227-A348239.

%K nonn

%O 0,2

%A _N. J. A. Sloane_, Oct 08 2021

%E More terms from _Rémy Sigrist_, Oct 09 2021