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A270571
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Numbers with at least one arithmetic progression of four consecutive divisors.
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2
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12, 24, 36, 48, 60, 72, 84, 96, 105, 108, 120, 132, 144, 156, 168, 180, 192, 204, 216, 228, 240, 252, 264, 276, 288, 300, 312, 315, 324, 336, 348, 360, 372, 384, 396, 408, 420, 432, 444, 456, 468, 480, 492, 504, 516, 525, 528, 540, 552, 564, 576, 588, 600
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OFFSET
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1,1
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COMMENTS
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Contrast A094529 where the divisors in arithmetic progression do not have to be consecutive.
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LINKS
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Harvey P. Dale, Table of n, a(n) for n = 1..1000
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EXAMPLE
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348 is included because its divisors are 1, 2, 3, 4, 6, 12, 29, 58, 87, 116, 174, and 348, and the first four are in arithmetic progression.
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MATHEMATICA
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ap4dQ[n_]:=Count[Partition[Divisors[n], 4, 1], _?(Length[ Union[ Differences[ #]]] == 1&)]>0; Select[ Range[700], ap4dQ]
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CROSSREFS
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Cf. A091011, A094529, A094530.
Sequence in context: A066085 A340511 A094529 * A044852 A121578 A044897
Adjacent sequences: A270568 A270569 A270570 * A270572 A270573 A270574
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller, Mar 19 2016
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EXTENSIONS
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Edited by Harvey P. Dale and Alois P. Heinz, Mar 19 2016
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STATUS
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approved
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