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A077219 Floor(geometric mean of the reduced residue system modulo n).

%I A077219 #2 Feb 11 2014 19:05:32
%S A077219 1,1,1,1,2,2,2,3,3,3,4,4,5,5,5,6,6,6,7,7,7,8,9,8,9,9,10,10,11,11,12,
%T A077219 12,12,12,12,13,14,14,14,14,15,15,16,16,16,16,17,17,18,18,18,19,20,19,
%U A077219 20,20,20,21,22,22,23,22,23,23,23,24,25,25,25,25,26,26,27,27,27,27,28,28
%N A077219 Floor(geometric mean of the reduced residue system modulo n).
%C A077219 1. The reduced residue system modulo n is the set of integers k between 1 and n which are coprime to n. The geometric mean of the positive integers a_1,...,a_n is the n-th root of a_1*...*a_n. 2. The arithmetic mean of the reduced residue system modulo n is A065033.
%t A077219 gm[l_] := Module[{k, p}, k = Length[l]; p = Product[l[[i]], {i, 1, k}]; p^(1/k)]; rp[n_] := Module[{a, i}, a = {1}; For[i = 2, i < n, i++, If[GCD[i, n] == 1, a = Append[a, i]]]; a];
%K A077219 nonn
%O A077219 1,5
%A A077219 _Joseph L. Pe_, Nov 30 2002