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%I #5 Dec 10 2012 11:28:46
%S 1,1,2,3,12,5,360,105,280,63,151200,385,9979200,6435,112112,675675,
%T 54486432000,85085,5557616064000,2909907,369512000,416645775,
%U 487847538097920000,37182145,8976394701001728,40542838875,2382036937280000,10756263375
%N Product of the radicals of the integers less than n and relatively prime to n.
%H C. M. Petridi, <a href="http://arxiv.org/abs/math/0608014">Note on the radicals of numbers</a>, arXiv:math/0608014.
%t Table[prod = 1; Do[If[GCD[n, i] == 1, prod = prod*Times @@ Transpose[FactorInteger[i]][[1]]], {i, n - 1}]; prod, {n, 30}] (* _T. D. Noe_, Dec 10 2012 *)
%o (PARI) a(n) = {local(p); p = 1; for (i=1, n, if (gcd(i, n) == 1, p *= A007947(i));); return (p);}
%Y Cf. A007947.
%K nonn
%O 1,3
%A _Michel Marcus_, Dec 09 2012