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A094529
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Numbers with at least one arithmetic progression of four divisors (not necessarily consecutive).
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3
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12, 24, 36, 48, 60, 72, 84, 96, 105, 108, 120, 132, 140, 144, 156, 168, 180, 192, 204, 210, 216, 228, 240, 252, 264, 276, 280, 288, 300, 312, 315, 324, 336, 348, 360, 372, 384, 396, 408, 420, 432, 440, 444, 456, 468, 480, 492, 504, 516, 525, 528, 540, 552, 560
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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COMMENTS
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All multiples of terms are also terms.
a(n) = m*A094530(k) for appropriate m and k.
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LINKS
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Alois P. Heinz, Table of n, a(n) for n = 1..10000
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MATHEMATICA
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sd4Q[n_]:=Count[Subsets[Divisors[n], {4}], _?(Length[Union[ Differences[ #]]] == 1&)]>0; Select[Range[600], sd4Q] (* Harvey P. Dale, Mar 19 2016 *)
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CROSSREFS
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Cf. A091011, A094530.
See A270571 for another version.
Sequence in context: A336657 A066085 A340511 * A270571 A044852 A121578
Adjacent sequences: A094526 A094527 A094528 * A094530 A094531 A094532
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller, May 07 2004
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EXTENSIONS
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Edited by Harvey P. Dale and Alois P. Heinz, Mar 18 2016
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STATUS
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approved
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