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URL: https://oeis.org/A292552

⇱ A292552 - OEIS

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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
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
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
KEYWORD
nonn
AUTHOR
Torlach Rush, Sep 18 2017
EXTENSIONS
More terms from Giovanni Resta, Sep 20 2017
STATUS
approved