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A251632
Circular disk sequence for the lattice of the Archimedean tiling (4,8,8).
3
1, 4, 5, 9, 15, 17, 19, 23, 28, 32, 33, 39, 41, 45, 47, 51, 53, 55, 59, 67, 71, 75, 78, 80, 82, 83, 85, 89, 93, 95, 99, 103, 107, 115, 117, 119, 121, 129, 133, 135, 137, 141, 143, 147, 149, 150, 154, 158, 160, 161, 169, 173, 177, 179, 183, 185, 187, 191, 193, 195, 199, 203, 205, 207, 211, 213
OFFSET
0,2
COMMENTS
For the squares of the radii of the lattice point hitting circles of the Archimedean tiling (4,8,8) see A251629 and A251631.
The first differences for this sequence are given in A251633.
See the link for more details.
FORMULA
a(n) is the number of lattice points of the Archimedean tiling (4,8,8) on the boundary and the interior of the circular disk belonging to the radius R(n) = sqrt(A251629(n) + A251631(n)*sqrt(2)), for n >= 0.
EXAMPLE
n=4: The radius of the disk is R(4) = sqrt(3 + 2*sqrt(2)), approximately 2.4142. The lattice points for this R(4)-disk are the origin, three points on the circle with radius R(1) = 1, one point on the circle with radius R(2) = sqrt(2), four points on the circle with radius R(3) = sqrt(2 + sqrt(2)) and 6 points on the circle with radius R(4) = sqrt(3 + 2*sqrt(2)), all together 1 + 3 + 1 + 4 + 6 = 15 = a(4) lattice points.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Wolfdieter Lang, Jan 02 2015
STATUS
approved