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 A120261 Number of primitive triangles with integer sides a<=b<=c and inradius n; primitive means gcd(a, b, c) = 1. 2
 1, 4, 10, 11, 13, 28, 17, 26, 31, 31, 20, 77, 28, 46, 67, 40, 28, 100, 26, 72, 120, 62, 32, 139, 44, 53, 71, 118, 32, 202, 35, 70, 135, 73, 97, 211, 33, 80, 130, 134, 36, 284, 45, 141, 183, 78, 50, 226, 68, 112, 150, 146, 38, 173, 150, 219, 182, 80, 38, 468, 36, 82 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 REFERENCES Mohammad K. Azarian, Circumradius and Inradius, Problem S125, Math Horizons, Vol. 15, Issue 4, April 2008, p. 32.  Solution published in Vol. 16, Issue 2, November 2008, p. 32. LINKS David W. Wilson, Table of n, a(n) for n = 1..10000 EXAMPLE a(3)=10 because 10 triangles have coprime integer sides and inradius 3, namely (7,24,25) (7,65,68) (8,15,17) (11,13,20) (12,55,65) (13,40,51) (15,28,41) (16,25,39) (19,20,37) (11,100,109). CROSSREFS Cf. A120062, A120252. See A120062 for sequences related to integer-sided triangles with integer inradius n. Sequence in context: A102535 A074226 A106631 * A310338 A101154 A182943 Adjacent sequences:  A120258 A120259 A120260 * A120262 A120263 A120264 KEYWORD nonn AUTHOR David W. Wilson, Jun 13 2006 STATUS approved

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Last modified September 20 11:42 EDT 2021. Contains 347584 sequences. (Running on oeis4.)