Totient¨1+↕25
⟨ 1 1 2 2 4 2 6 4 6 4 10 4 12 6 8 8 16 6 18 8 12 10 22 8 20 ⟩

   "Number"‿"Totient"‿"Prime?"∾˘{𝕩∾(⊢≍(𝕩-1)⊸=)Totient¨𝕩}1+↕25
┌─
╵ "Number"  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
  "Totient" 1 1 2 2 4 2 6 4 6 4  10 4  12 6  8  8  16 6  18 8  12 10 22 8  20
  "Prime?"  0 1 1 0 1 0 1 0 0 0  1  0  1  0  0  0  1  0  1  0  0  0  1  0  0
                                                                              ┘