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A070106
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Number of integer triangles with perimeter n which are obtuse and isosceles.
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5
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0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 2, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 3, 2, 2, 3, 3, 2, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 3, 3, 4, 4, 3, 3, 4, 4, 3, 4, 4
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OFFSET
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1,31
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COMMENTS
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a(n)=A070101(n)-A024156(n); a(n)=A059169(n)-A070098(n).
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LINKS
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Table of n, a(n) for n=1..90.
R. Zumkeller, Integer-sided triangles
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EXAMPLE
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For n=11 there are A005044(11)=4 integer triangles: [1,5,5], [2,4,5], [3,3,5] and [3,4,4]; only one of the two obtuses ([2,4,5] and [3=3,5]) is als isosceles, therefore a(11)=1.
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CROSSREFS
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Cf. A070080, A070081, A070082, A059169, A070107, A070108, A070133.
Sequence in context: A157230 A034380 A077479 * A182595 A109706 A174541
Adjacent sequences: A070103 A070104 A070105 * A070107 A070108 A070109
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller, May 05 2002
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STATUS
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approved
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