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A122904
Numbers n such that in Z/nZ the number of squares is strictly less than the number of invertible elements.
5
5, 7, 8, 9, 11, 13, 15, 16, 17, 19, 20, 21, 23, 24, 25, 27, 28, 29, 31, 32, 33, 35, 36, 37, 39, 40, 41, 43, 44, 45, 47, 48, 49, 51, 52, 53, 55, 56, 57, 59, 60, 61, 63, 64, 65, 67, 68, 69, 71, 72, 73, 75, 76, 77, 79, 80, 81, 83, 84, 85, 87, 88, 89, 91, 92, 93, 95, 96, 97, 99, 100
OFFSET
1,1
LINKS
FORMULA
n such that A000224(n) < A000010(n)
MATHEMATICA
Select[Range@100, Length@Union@Mod[Range[#]^2, #] < EulerPhi[#] &] (* Ivan Neretin, Dec 14 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Max Alekseyev, Sep 18 2006
STATUS
approved