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A270571
Numbers with at least one arithmetic progression of four consecutive divisors.
2
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
OFFSET
1,1
COMMENTS
Contrast A094529 where the divisors in arithmetic progression do not have to be consecutive.
LINKS
EXAMPLE
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.
MATHEMATICA
ap4dQ[n_]:=Count[Partition[Divisors[n], 4, 1], _?(Length[ Union[ Differences[ #]]] == 1&)]>0; Select[ Range[700], ap4dQ]
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Mar 19 2016
EXTENSIONS
Edited by Harvey P. Dale and Alois P. Heinz, Mar 19 2016
STATUS
approved