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

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Mar 19 2016

EXTENSIONS

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

STATUS

approved