A171090 Number of Apollonian packings of n circles that are Eulerian and irreducible.

1, 0, 1, 0, 2, 1, 5, 3, 18, 19, 79, 134, 501, 1147, 3976, 11055, 37231, 114560, 384053, 1244056, 4193857, 13977946, 47522279, 161222224, 553033544, 1899744032, 6571595339, 22793047258, 79449718217, 277760027418, 974836112457

Offset

6,5

Links

Table of n, a(n) for n=6..36.

G. Brinkmann, and B.D. McKay, Guide to using plantri (version 4.1).

Gunnar Brinkmann and Brendan McKay, Guide to using plantri [Cached copy, with permission]

S. Butler et al., Irreducible Apollonian configurations and packings, Discrete and Computational Geometry, 44 (2010), 487-507.

CombOS - Combinatorial Object Server, Generate planar graphs

Crossrefs

Sequence in context: A194809 A113178 A108362 * A141506 A345454 A271684

Adjacent sequences: A171087 A171088 A171089 * A171091 A171092 A171093

Keyword

nonn

Author

N. J. A. Sloane, Sep 08 2010

Extensions

More terms from plantri added by Sean A. Irvine, Jun 22 2016

Status

approved