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Search: id:A130611
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| A130611 |
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Tribonacci numbers which can be the hypotenuse of a Pythagorean triple. |
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+0
1
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| 13, 149, 274, 1705, 19513, 35890, 66012, 121415, 755476, 1389537, 4700770
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The first 2 values are hypotenuses of primitive Pythagorean triples, A000073 INTERSECTION A020882: (5^2 + 12^2 = 13^2), (51^2 + 140^2 = 149^2). The other values listed have one or more nonprimitive solution: a(6) = 35890 has 13 solutions; a(8), a(9), a(10), a(11) have 4 solutions each.
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FORMULA
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A000073 INTERSECTION A009000. {c in A000073 such that there exist integers a, b with a^2 + b^2 = c^2}.
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EXAMPLE
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a(4) = 1705 because 1023^2 + 1364^2 = 1705^2, which is a nonprimitive Pythagoran triple 341*(3,4,5).
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CROSSREFS
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Cf. A000073, A020882, A009000.
Adjacent sequences: A130608 A130609 A130610 this_sequence A130612 A130613 A130614
Sequence in context: A110748 A016135 A132156 this_sequence A127747 A090667 A125448
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KEYWORD
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easy,nonn
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AUTHOR
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Jonathan Vos Post (jvospost2(AT)yahoo.com), Jun 17 2007
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