A226746 Numbers n such that x^2 = 1 has more than two solutions in the Gaussian integers modulo n.
4, 5, 6, 8, 10, 12, 13, 14, 15, 16, 17, 18, 20, 21, 22, 24, 25, 26, 28, 29, 30, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 44, 45, 46, 48, 50, 51, 52, 53, 54, 55, 56, 57, 58, 60, 61, 62, 63, 64, 65, 66, 68, 69, 70, 72, 73, 74, 75, 76, 77, 78, 80, 82, 84, 85
Offset: 1
Keywords
Examples
13 is in the sequence because 5i, 8i, 1 and 12 are solutions of x^2 = 1 (mod 13).
Programs
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Mathematica
h[n_] := Flatten[Table[a + b I, {a, 0, n - 1}, {b, 0, n - 1}]]; sol[n_] := Select[h[n], Mod[#^2, n] == 1 &]; Select[Range[100], Length[sol[#]] > 2 &]