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A359970
Number of edges formed inside a right triangle by the straight line segments mutually connecting all vertices and points on the two shorter edges whose positions equal the Farey series of order n.
5
3, 10, 84, 433, 3264, 7357, 37065, 86441, 232975, 405510, 1210898, 1773121, 4500787, 6774404, 10997356
OFFSET
1,1
COMMENTS
The number of vertices along the shorter edges is A005728(n). No formula for a(n) is known. The sequence is inspired by the Farey fan; see A360042.
See A359968 and A359969 for images of the triangle.
FORMULA
a(n) = A359968(n) + A359969(n) - 1 by Euler's formula.
CROSSREFS
Cf. A359968 (vertices), A359969 (regions), A359971 (k-gons), A005728, A360042, A359976, A359693, A358950, A358888.
Sequence in context: A203492 A320258 A136554 * A341848 A136505 A006311
KEYWORD
nonn,more
AUTHOR
STATUS
approved