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%I #17 Mar 19 2018 22:10:28
%S 1,2,3,2,5,3,7,4,3,5,11,2,13,7,5,4,17,3,19,5,7,11,23,2,5,13,9,7,29,1,
%T 31,8,11,17,7,3,37,19,13,2,41,7,43,11,3,23,47,4,7,5,17,13,53,9,11,2,
%U 19,29,59,1,61,31,3,8,13,11,67,17,23,1,71,3,73,37,5,19,11,13,79,2,9,41,83
%N a(n) = n / (LCM of divisors of n which are <= sqrt(n)).
%H Robert Israel, <a href="/A072505/b072505.txt">Table of n, a(n) for n = 1..10000</a>
%F From _Robert Israel_, Mar 19 2018: (Start)
%F If n = p^k for prime p, then a(n) = p^ceiling(k/2).
%F In particular, a(n) = n if and only if n is prime.
%F If n = p*q for primes p < q, then a(n) = q. (End)
%e a(20) = 5: the divisors of 20 are 1,2,4,5,10 and 20; a(20) = 20/lcm(1,2,4) = 20/4 = 5.
%p f:= proc(n) n/ilcm(op(select(t -> t^2 <= n, numtheory:-divisors(n)))) end proc:
%p map(f, [$1..100]); # _Robert Israel_, Mar 19 2018
%t lc[n_]:=Module[{c=Select[Divisors[n],#<=Sqrt[n]&]},n/LCM@@c]; Array[lc,90] (* _Harvey P. Dale_, May 18 2012 *)
%Y Cf. A072504.
%K nonn,look
%O 1,2
%A _Amarnath Murthy_, Jul 20 2002
%E Corrected and extended by _Matthew Conroy_, Sep 09 2002
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