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A129511 Numbers such that all differences between distinct divisors occur exactly once.

%I A129511 #16 Jan 21 2025 23:57:12
%S A129511 1,2,3,4,5,7,8,9,10,11,13,14,16,17,19,21,22,23,25,26,27,29,31,32,33,
%T A129511 34,35,37,38,39,41,43,44,46,47,49,50,51,52,53,55,57,58,59,61,62,64,65,
%U A129511 67,68,69,71,73,74,76,77,79,81,82,83,85,86,87,89,92,93,94,95,97,98,101,103
%N A129511 Numbers such that all differences between distinct divisors occur exactly once.
%C A129511 A129510(a(n)) = A066446(a(n)).
%C A129511 a(n) = A174905(n) for n<27, A174905(27)=37 whereas a(27)=35. - _Reinhard Zumkeller_, Apr 01 2010
%H A129511 Reinhard Zumkeller, <a href="/A129511/b129511.txt">Table of n, a(n) for n = 1..10000</a>
%e A129511 See example for a(33)=44 in A129510.
%t A129511 Select[Range[103],CountDistinct[Differences /@ Subsets[Divisors[#], {2}]]==Length[Flatten[Differences /@ Subsets[Divisors[#], {2}]]]&] (* _James C. McMahon_, Jan 21 2025 *)
%o A129511 (Haskell)
%o A129511 import Data.List.Ordered (isect, union)
%o A129511 a129511 n = a129511_list !! (n-1)
%o A129511 a129511_list = filter (f [] . a027750_row') [1..] where
%o A129511    f _ [_] = True
%o A129511    f zs (d:ds) = null (dds `isect` zs) && f (dds `union` zs) ds
%o A129511                  where dds = map (subtract d) ds
%o A129511 -- _Reinhard Zumkeller_, Jun 25 2015
%Y A129511 Cf. A027750, A066446, A129510, A129512 (complement), A174905.
%K A129511 nonn
%O A129511 1,2
%A A129511 _Reinhard Zumkeller_, Apr 19 2007