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A348229
Coordination sequence for Wilkinson's 123-circle packing with respect to a circle of radius 2.
3
1, 6, 16, 24, 38, 40, 58, 56, 78, 72, 98, 88, 118, 104, 138, 120, 158, 136, 178, 152, 198, 168, 218, 184, 238, 200, 258, 216, 278, 232, 298, 248, 318, 264, 338, 280, 358, 296, 378, 312, 398, 328, 418, 344, 438, 360, 458, 376, 478, 392, 498, 408, 518, 424, 538
OFFSET
0,2
COMMENTS
See A348227 for much more information about this structure.
FORMULA
G.f. = (1 + 6*q + 14*q^2 + 12*q^3 + 7*q^4 - 2*q^5 - 2*q^6)/(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.]
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Oct 08 2021
EXTENSIONS
More terms from Rémy Sigrist, Oct 09 2021
STATUS
approved