A270571 Numbers with at least one arithmetic progression of four consecutive divisors.

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

Harvey P. Dale, Table of n, a(n) for n = 1..1000

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

Cf. A091011, A094529, A094530.

Sequence in context: A066085 A340511 A094529 * A044852 A121578 A044897

Adjacent sequences: A270568 A270569 A270570 * A270572 A270573 A270574

Keyword

nonn

Author

Reinhard Zumkeller, Mar 19 2016

Extensions

Edited by Harvey P. Dale and Alois P. Heinz, Mar 19 2016

Status

approved