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A067749 Numbers k such that k and 3^k end with the same two digits. 0

%I

%S 87,187,287,387,487,587,687,787,887,987,1087,1187,1287,1387,1487,1587,

%T 1687,1787,1887,1987,2087,2187,2287,2387,2487,2587,2687,2787,2887,

%U 2987,3087,3187,3287,3387,3487,3587,3687,3787,3887,3987,4087,4187,4287,4387

%N Numbers k such that k and 3^k end with the same two digits.

%H Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/RecursiveSequences.html">Recursive Sequences</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).

%F a(n) = 100*n - 13.

%t 100*Range[50]-13 (* or *) LinearRecurrence[{2,-1},{87,187},50] (* _Harvey P. Dale_, Jul 18 2016 *)

%o (PARI) a(n) = 100*n - 13; \\ _Jinyuan Wang_, Apr 05 2020

%K nonn,base,easy

%O 1,1

%A _Benoit Cloitre_, Mar 07 2002

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Last modified December 2 05:23 EST 2020. Contains 338865 sequences. (Running on oeis4.)