A094529 Numbers with at least one arithmetic progression of four divisors (not necessarily consecutive).

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

Offset

1,1

Comments

All multiples of terms are also terms.

a(n) = m*A094530(k) for appropriate m and k.

Links

Alois P. Heinz, Table of n, a(n) for n = 1..10000

Mathematica

sd4Q[n_]:=Count[Subsets[Divisors[n], {4}], _?(Length[Union[ Differences[ #]]] == 1&)]>0; Select[Range[600], sd4Q] (* Harvey P. Dale, Mar 19 2016 *)

Crossrefs

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

Keyword

nonn

Author

Reinhard Zumkeller, May 07 2004

Extensions

Edited by Harvey P. Dale and Alois P. Heinz, Mar 18 2016

Status

approved