A187208 Numbers such that the last of the absolute differences of divisors is 1.

1, 2, 4, 8, 12, 16, 20, 32, 36, 48, 64, 80, 108, 112, 128, 156, 192, 204, 220, 252, 256, 260, 272, 304, 320, 324, 368, 396, 448, 476, 484, 512, 544, 608, 656, 660, 688, 768, 972, 1008, 1024, 1044, 1120, 1184, 1248, 1280, 1300, 1332, 1476, 1764, 1792, 1908

Offset

1,2

Comments

Numbers n such that A187203(n) = 1.

A000079 is a subsequence (powers of 2). [Reinhard Zumkeller, Aug 02 2011]

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Mathematica

lad1Q[n_]:=Nest[Abs[Differences[#]]&, Divisors[n], DivisorSigma[0, n]-1]=={1}; Select[Range[2000], lad1Q] (* Harvey P. Dale, Nov 07 2022 *)

Prog

(Haskell)
import Data.List (elemIndices)
a187208 n = a187208_list !! (n-1)
a187208_list = map (+ 1) $ elemIndices 1 $ map a187203 [1..]
-- Reinhard Zumkeller, Aug 02 2011

Crossrefs

Cf. A027750, A187202, A187203, A187204, A187205.

Sequence in context: A160742 A160736 A118030 * A349725 A351623 A256409

Adjacent sequences: A187205 A187206 A187207 * A187209 A187210 A187211

Keyword

nonn

Author

Omar E. Pol, Aug 01 2011

Status

approved