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

Author

Omar E. Pol, Aug 01 2011

Keywords

• nonn

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

Crossrefs

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

Programs

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

Mathematica

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