euler-totient-function.egi

(define $φ
  (lambda [$n]
    (* n
       (product (map (lambda [$p] (- 1 (/ 1 p)))
                     (unique (p-f n)))))))

(take 100 (map2 2#[%1 %2 (p-f %2)] nats (map φ nats)))

{[1 1 {}]
 [2 1 {}]
 [3 2 {2}]
 [4 2 {2}]
 [5 4 {2 2}]
 [6 2 {2}]
 [7 6 {2 3}]
 [8 4 {2 2}]
 [9 6 {2 3}]
 [10 4 {2 2}]
 [11 10 {2 5}]
 [12 4 {2 2}]
 [13 12 {2 2 3}]
 [14 6 {2 3}]
 [15 8 {2 2 2}]
 [16 8 {2 2 2}]
 [17 16 {2 2 2 2}]
 [18 6 {2 3}]
 [19 18 {2 3 3}]
 [20 8 {2 2 2}]
 [21 12 {2 2 3}]
 [22 10 {2 5}]
 [23 22 {2 11}]
 [24 8 {2 2 2}]
 [25 20 {2 2 5}]
 [26 12 {2 2 3}]
 [27 18 {2 3 3}]
 [28 12 {2 2 3}]
 [29 28 {2 2 7}]
 [30 8 {2 2 2}]
 [31 30 {2 3 5}]
 [32 16 {2 2 2 2}]
 [33 20 {2 2 5}]
 [34 16 {2 2 2 2}]
 [35 24 {2 2 2 3}]
 [36 12 {2 2 3}]
 [37 36 {2 2 3 3}]
 [38 18 {2 3 3}]
 [39 24 {2 2 2 3}]
 [40 16 {2 2 2 2}]
 [41 40 {2 2 2 5}]
 [42 12 {2 2 3}]
 [43 42 {2 3 7}]
 [44 20 {2 2 5}]
 [45 24 {2 2 2 3}]
 [46 22 {2 11}]
 [47 46 {2 23}]
 [48 16 {2 2 2 2}]
 [49 42 {2 3 7}]
 [50 20 {2 2 5}]
 [51 32 {2 2 2 2 2}]
 [52 24 {2 2 2 3}]
 [53 52 {2 2 13}]
 [54 18 {2 3 3}]
 [55 40 {2 2 2 5}]
 [56 24 {2 2 2 3}]
 [57 36 {2 2 3 3}]
 [58 28 {2 2 7}]
 [59 58 {2 29}]
 [60 16 {2 2 2 2}]
 [61 60 {2 2 3 5}]
 [62 30 {2 3 5}]
 [63 36 {2 2 3 3}]
 [64 32 {2 2 2 2 2}]
 [65 48 {2 2 2 2 3}]
 [66 20 {2 2 5}]
 [67 66 {2 3 11}]
 [68 32 {2 2 2 2 2}]
 [69 44 {2 2 11}]
 [70 24 {2 2 2 3}]
 [71 70 {2 5 7}]
 [72 24 {2 2 2 3}]
 [73 72 {2 2 2 3 3}]
 [74 36 {2 2 3 3}]
 [75 40 {2 2 2 5}]
 [76 36 {2 2 3 3}]
 [77 60 {2 2 3 5}]
 [78 24 {2 2 2 3}]
 [79 78 {2 3 13}]
 [80 32 {2 2 2 2 2}]
 [81 54 {2 3 3 3}]
 [82 40 {2 2 2 5}]
 [83 82 {2 41}]
 [84 24 {2 2 2 3}]
 [85 64 {2 2 2 2 2 2}]
 [86 42 {2 3 7}]
 [87 56 {2 2 2 7}]
 [88 40 {2 2 2 5}]
 [89 88 {2 2 2 11}]
 [90 24 {2 2 2 3}]
 [91 72 {2 2 2 3 3}]
 [92 44 {2 2 11}]
 [93 60 {2 2 3 5}]
 [94 46 {2 23}]
 [95 72 {2 2 2 3 3}]
 [96 32 {2 2 2 2 2}]
 [97 96 {2 2 2 2 2 3}]
 [98 42 {2 3 7}]
 [99 60 {2 2 3 5}]
 [100 40 {2 2 2 5}]}