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

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, 12, 12, 12, 12, 13, 14, 14, 14, 14, 15, 15, 16, 16, 16, 16, 17, 17, 18, 18, 18, 19, 20, 19, 20, 20, 20, 21, 22, 22, 23, 22, 23, 23, 23, 24, 25, 25, 25, 25, 26, 26, 27, 27, 27, 27, 28, 28

Offset: 1

Author

Joseph L. Pe, Nov 30 2002

Keywords

• nonn

Comments

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.

Programs

Mathematica

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];