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%I #30 Feb 20 2024 06:59:39
%S 1,3,5,7,13,17,32,38,67,137,203,247,472,578,682,787,1463,2047,2363,
%T 3465,5197,5198,8662,13513,15593,22522,22523,29452,60638,67567,67568,
%U 98753,112612,157658,202702,337837,337838,427927,713212,788287,788288,1013512
%N Number of anti-divisors of n (A066272) sets a record.
%C antid(n) > antid(k) for all k < n.
%C Note that several of these come in pairs, i.e., 5197 & 5198, 22522 & 22523, 67567 & 67568, 337837 & 337838, 788287 & 788288, 1013512 & 1013513 and 1914412 & 1914413 to name a few. See A093071 for more. - _Robert G. Wilson v_, Mar 17 2004
%C See A066272 for definition of anti-divisor.
%H Donovan Johnson, <a href="/A073638/b073638.txt">Table of n, a(n) for n = 1..117</a> (terms < 5*10^11)
%H Jon Perry, <a href="http://www.users.globalnet.co.uk/~perry/maths">Anti-divisors</a>.
%H Jon Perry, <a href="/A066272/a066272a.html">The Anti-divisor</a> [Cached copy]
%H Jon Perry, <a href="/A066272/a066272.html">The Anti-divisor: Even More Anti-Divisors</a> [Cached copy]
%t antid[n_] := Select[ Union[ Join[ Select[ Divisors[2n - 1], OddQ[ # ] && # != 1 &], Select[ Divisors[2n + 1], OddQ[ # ] && # != 1 & ], 2n/Select[ Divisors[ 2n], OddQ[ # ] && # != 1 &]]], # < n &]; a = 0; Do[b = Length[ antid[ n]]; If[b > a, Print[n]; a = b], {n, 1, 1013513}] (* _Robert G. Wilson v_, Mar 17 2004 *)
%K nonn
%O 1,2
%A _Jason Earls_, Sep 01 2002
%E More terms from _Robert G. Wilson v_, Mar 17 2004
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