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Search: id:A120252
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| A120252 |
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Number of primitive triangles with integer sides a<=b<=c and inradius n; primitive means gcd(a, b, c, n) = 1. |
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+0
5
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| 1, 4, 12, 13, 14, 28, 23, 27, 38, 33, 25, 81, 30, 52, 83, 44, 32, 101, 33, 80, 149, 73, 41, 146, 50, 61, 89, 132, 35, 204, 45, 80, 173, 79, 135, 220, 37, 85, 167, 156, 43, 291, 59, 164, 234, 88, 63, 236, 92, 126, 185, 162, 46, 179, 189, 258, 230, 94, 53, 483, 43, 94
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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A120062(n) = sum_{k:k|n} a(k)
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LINKS
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David W. Wilson, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Heronian Triangle
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FORMULA
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Moebius transform of A120062. - David W. Wilson (davidwwilson(AT)comcast.net), Jun 14 2006
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EXAMPLE
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a(3)= 12 because there are 12 primitive triangles with integer sides and inradius r=3. They are (10,10,12), (8,15,17), (11,13,20), (7,24,25), (8,26,30), (19,20,37), (16,25,39), (15,28,41), (13,40,51), (12,55,65), (7,65,68), (11,100,109).
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CROSSREFS
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Cf. A120062.
See A120062 for sequences related to integer-sided triangles with integer inradius n.
Sequence in context: A009115 A051434 A074138 this_sequence A103053 A087760 A032498
Adjacent sequences: A120249 A120250 A120251 this_sequence A120253 A120254 A120255
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KEYWORD
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nonn
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AUTHOR
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Graeme McRae (g_m(AT)mcraefamily.com), Jun 12 2006
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