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 A071386 Numbers n such that cardinality of InvPhi[n] is odd. 5
 2, 8, 20, 32, 40, 44, 48, 56, 60, 72, 92, 96, 104, 108, 116, 120, 128, 132, 140, 144, 156, 164, 192, 204, 212, 216, 220, 240, 252, 260, 272, 276, 296, 300, 332, 344, 356, 360, 368, 380, 384, 392, 396, 400, 416, 420, 440, 444, 452, 456, 476, 480, 500, 504, 512 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..55. FORMULA Mod[Card[InvPhi(n)], 2]=1 EXAMPLE n=40:InvPhi[40]={41,55,75,82,88,100,110,132,150} has 9 entries. CROSSREFS Cf. A000010, A014197, A058277, A063512, A071397. Sequence in context: A110856 A048041 A217513 * A031114 A327100 A130238 Adjacent sequences: A071383 A071384 A071385 * A071387 A071388 A071389 KEYWORD nonn AUTHOR Labos Elemer, May 23 2002 STATUS approved

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Last modified December 5 20:27 EST 2023. Contains 367594 sequences. (Running on oeis4.)