A332019 The number of cells added in the n-th generation of the following procedure: start by coloring any triangle on the snub square tiling, then repeatedly color every cell that shares a vertex with a colored cell.

1, 9, 21, 35, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156, 168, 180, 192, 204, 216, 228, 240, 252, 264, 276, 288, 300, 312, 324, 336, 348, 360, 372, 384, 396, 408, 420, 432, 444, 456, 468, 480, 492, 504, 516, 528, 540, 552, 564, 576, 588, 600, 612, 624, 636

Offset

1,2

Links

Peter Kagey, Table of n, a(n) for n = 1..1000

Code Golf Stack Exchange, Concentric rings on a snub square tiling.

Index entries for linear recurrences with constant coefficients, signature (2,-1).

Formula

a(n) = 12*(n - 1) for n > 4.

From Stefano Spezia, Feb 05 2020: (Start)

G.f.: x*(1 + 7*x + 4*x^2 + 2*x^3 - x^4 - x^5)/(-1 + x)^2.

a(n) = 2*a(n-1) - a(n-2) for n > 6.

(End)

Crossrefs

Cf. A008594.

A296368 is the analogous sequence when instead coloring every cell that shares a side with a colored cell.

Sequence in context: A253052 A043112 A043892 * A146069 A140673 A186294

Adjacent sequences: A332016 A332017 A332018 * A332020 A332021 A332022

Keyword

easy,nonn

Author

Peter Kagey, Feb 04 2020

Status

approved