A298016 Coordination sequence of snub-632 tiling with respect to a hexavalent node.

1, 6, 12, 12, 24, 36, 24, 42, 60, 36, 60, 84, 48, 78, 108, 60, 96, 132, 72, 114, 156, 84, 132, 180, 96, 150, 204, 108, 168, 228, 120, 186, 252, 132, 204, 276, 144, 222, 300, 156, 240, 324, 168, 258, 348, 180, 276, 372, 192, 294, 396, 204, 312, 420, 216, 330, 444, 228, 348, 468, 240

Offset: 0

Author

Chaim Goodman-Strauss and N. J. A. Sloane, Jan 11 2018

Keywords

• nonn
• easy

Comments

The snub-632 tiling in also called the fsz-d net. It is the dual of the 3.3.3.3.6 Archimedean tiling.

This is also called the "6-fold pentille" tiling in Conway, Burgiel, Goodman-Strauss, 2008, p. 288. - Felix Fröhlich, Jan 13 2018

References

• J. H. Conway, H. Burgiel and Chaim Goodman-Strauss, The Symmetries of Things, A K Peters, Ltd., 2008, ISBN 978-1-56881-220-5.

Links

• Colin Barker, Table of n, a(n) for n = 0..1000
• Chaim Goodman-Strauss and N. J. A. Sloane, A Coloring Book Approach to Finding Coordination Sequences, Acta Cryst. A75 (2019), 121-134, also on NJAS's home page. Also arXiv:1803.08530.
• Chaim Goodman-Strauss and N. J. A. Sloane, Trunks and branches structure for calculating this sequence
• Tom Karzes, Tiling Coordination Sequences
• N. J. A. Sloane, Overview of coordination sequences of Laves tilings [Fig. 2.7.1 of Grünbaum-Shephard 1987 with A-numbers added and in some cases the name in the RCSR database]
• Index entries for linear recurrences with constant coefficients, signature (0,0,2,0,0,-1).

Crossrefs

Cf. A298014, A298015.

List of coordination sequences for Laves tilings (or duals of uniform planar nets): [3,3,3,3,3.3] = A008486; [3.3.3.3.6] = A298014, A298015, A298016; [3.3.3.4.4] = A298022, A298024; [3.3.4.3.4] = A008574, A296368; [3.6.3.6] = A298026, A298028; [3.4.6.4] = A298029, A298031, A298033; [3.12.12] = A019557, A298035; [4.4.4.4] = A008574; [4.6.12] = A298036, A298038, A298040; [4.8.8] = A022144, A234275; [6.6.6] = A008458.

Programs

Maple

f:=proc(n) local k,r;
if n=0 then return(1); fi;
r:=(n mod 3); k:=(n-r)/3;
if r=0 then 12*k elif r=1 then 18*k+6 else 24*k+12; fi;
end;
[seq(f(n),n=0..80)];

Mathematica

Join[{1}, LinearRecurrence[{0, 0, 2, 0, 0, -1}, {6, 12, 12, 24, 36, 24}, 60]] (* Jean-François Alcover, Apr 23 2018 *)

PARI

Vec((1 + 6*x + 12*x^2 + 10*x^3 + 12*x^4 + 12*x^5 + x^6) / ((1 - x)^2*(1 + x + x^2)^2) + O(x^60)) \\ Colin Barker, Jan 13 2018

Formula

For n >= 1, let k=floor(n/3). Then a(3*k) = 12*k, a(3*k+1)=18*k+6, a(3*k+2)=24*k+12.

a(n) = 2*a(n-3) - a(n-6) for n >= 7.

G.f.: -(-x^6-12*x^5-12*x^4-10*x^3-12*x^2-6*x-1)/(x^6-2*x^3+1).