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 A292552 Nontotients of the form 10^k - 2. 0
 98, 998, 9998, 99998, 999998, 9999998, 99999998, 999999998, 9999999998, 99999999998, 999999999998, 9999999999998, 99999999999998, 999999999999998, 9999999999999998, 99999999999999998, 999999999999999998, 9999999999999999998, 99999999999999999998 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS There are no k for which (2^n)*(5^n)[p1*p2*...*pk]-2[p1*p2*...*pk]=m[(p1-1)*(p2-1)*...*(pk-1)]. Up to k = 60, the only totient of the form 10^k-2 is obtained for k=1. - Giovanni Resta, Sep 20 2017 For 10^k-2 with k > 1 to be a totient, it would have to be of the form (p-1)*p^m for some odd prime p and m >= 2. - Robert Israel, Sep 20 2017 LINKS Table of n, a(n) for n=1..19. EXAMPLE a(1) = A011557(2) - 2 = A005277(13); a(2) = A011557(3) - 2 = A005277(210); a(3) = A011557(4) - 2 = A005277(2627); a(4) = A011557(5) - 2 = A005277(29747). CROSSREFS Cf. A005277, A011557. Sequence in context: A202370 A184608 A088736 * A233373 A221747 A190636 Adjacent sequences: A292549 A292550 A292551 * A292553 A292554 A292555 KEYWORD nonn AUTHOR Torlach Rush, Sep 18 2017 EXTENSIONS More terms from Giovanni Resta, Sep 20 2017 STATUS approved

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Last modified May 30 10:19 EDT 2023. Contains 363050 sequences. (Running on oeis4.)