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%I #10 Feb 23 2024 01:09:54
%S 38,45,52,53,58,59,63,68,73,82,83,87,88,93,97,102,103,104,108,110,116,
%T 117,126,133,135,136,138,140,142,147,153,161,163,167,170,173,176,179,
%U 192,198,199,210,229,231,232,233,234,235,243,245,252,258,259,267,269
%N Numbers having just seven anti-divisors.
%C See A066272 for definition of anti-divisor.
%H Jon Perry, <a href="http://www.users.globalnet.co.uk/~perry/maths/antidivisor.htm">The Anti-Divisor</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[ 2*n], OddQ[ # ] && # != 1 &]]] }, # < n & ]]; Select[ Range[10^4], Length[ antid[ # ]] == 7 & ]
%Y Cf. A066272.
%K nonn
%O 1,1
%A _Robert G. Wilson v_, Jan 02 2002
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