A187208 - OEIS

%I #16 Nov 07 2022 12:12:59

%S 1,2,4,8,12,16,20,32,36,48,64,80,108,112,128,156,192,204,220,252,256,

%T 260,272,304,320,324,368,396,448,476,484,512,544,608,656,660,688,768,

%U 972,1008,1024,1044,1120,1184,1248,1280,1300,1332,1476,1764,1792,1908

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

%C Numbers n such that A187203(n) = 1.

%C A000079 is a subsequence (powers of 2). [_Reinhard Zumkeller_, Aug 02 2011]

%H Reinhard Zumkeller, <a href="/A187208/b187208.txt">Table of n, a(n) for n = 1..1000</a>

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

%o (Haskell)

%o import Data.List (elemIndices)

%o a187208 n = a187208_list !! (n-1)

%o a187208_list = map (+ 1) $ elemIndices 1 $ map a187203 [1..]

%o -- _Reinhard Zumkeller_, Aug 02 2011

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

%K nonn

%O 1,2

%A _Omar E. Pol_, Aug 01 2011