A348229 Coordination sequence for Wilkinson's 123-circle packing with respect to a circle of radius 2.

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.

Links

Table of n, a(n) for n=0..54.

Rémy Sigrist, PARI program for A348229

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

Cf. A348227-A348239.

Sequence in context: A034053 A199988 A114222 * A275641 A171440 A031220

Adjacent sequences: A348226 A348227 A348228 * A348230 A348231 A348232

Keyword

nonn

Author

N. J. A. Sloane, Oct 08 2021

Extensions

More terms from Rémy Sigrist, Oct 09 2021

Status

approved