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A370979
Draw a regular n-gon and the enclosing circle, then for each pair of vertices X, Y, draw a circle with diameter XY; the union of these figures is the graph H_n; sequence gives number of edges in H_n.
6
1, 4, 21, 20, 135, 144, 553, 440, 1575, 1460, 3729, 3132, 7527, 6888, 13605, 12016, 23307, 20988, 36385, 32420, 54915, 51216, 79741, 70776, 113175, 105300, 154845, 144508, 206799, 195840, 272893, 255840, 352275, 335036, 446845, 422820, 561031, 534736, 695877, 659480, 850463, 815724
OFFSET
1,2
COMMENTS
For the numbers of vertices and regions in G_n see A358746 and A370978.
H_n is the union of the graph G_n defined in A370976 and the polygon through the initial n points.
FORMULA
a(n) = A358783(n) if n even, a(n) = A358783(n) + n if n odd.
a(n) = A358783(n) + n if n even, a(n) = A358783(n) + 3*n if n odd.
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved