A122907 Numbers m such that in Z/mZ the number of squares is greater than or equal to the number of invertible elements.

1, 2, 3, 4, 6, 10, 12, 14, 18, 22, 26, 30, 34, 38, 42, 46, 50, 54, 58, 62, 66, 70, 74, 78, 82, 86, 90, 94, 98, 102, 106, 114, 118, 122, 134, 138, 142, 146, 150, 158, 162, 166, 174, 178, 186, 194, 202, 206, 210, 214, 218, 222, 226, 242, 246, 250, 254, 258, 262, 274

Offset

1,2

Comments

Numbers m such that A000224(m) >= A000010(m).

Links

Ivan Neretin, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range@275, Length@Union@Mod[Range[#]^2, #] >= EulerPhi[#] &] (* Ivan Neretin, Dec 14 2016 *)
f1[p_, e_] := Floor[p^(e+1)/(2p + 2)] + 1; f1[2, e_] := Floor[2^e/6] + 2; f[p_, e_] := f1[p, e]/((p-1) * p^(e-1)); q[1] = True; q[k_] := Times @@ f @@@ FactorInteger[k] >= 1; Select[Range[300], q] (* Amiram Eldar, Nov 11 2024 *)

Crossrefs

Union of A122903 and A122905.

Complement of A122904 in positive integers.

Cf. A000010, A000224, A122906.

Sequence in context: A225651 A191149 A344552 * A070519 A177913 A098392

Adjacent sequences: A122904 A122905 A122906 * A122908 A122909 A122910

Keyword

nonn

Author

Max Alekseyev, Sep 18 2006

Status

approved