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Numbers k such that 13^k has no zero in its decimal expansion.
21

%I #26 May 24 2023 19:01:49

%S 0,1,2,3,4,5,7,10,14

%N Numbers k such that 13^k has no zero in its decimal expansion.

%C Probably finite. Is 14 the largest term?

%H Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_607.htm">Puzzle 607. A zeroless Prime power</a>

%F Equals { n | A001022(n) is in A052382 }.

%t Select[Range[0,20],DigitCount[13^#,10,0]==0&] (* _Harvey P. Dale_, May 24 2023 *)

%o (PARI) for( n=0,9999, is_A052382(13^n) && print1(n","))

%o (Magma) [n: n in [0..1000] | not 0 in Intseq(13^n) ]; // _Vincenzo Librandi_, May 06 2015

%Y Cf. A195942, A195943, A195945, A195946, A195908, A195948, A052382, A007377, A008839, A030700, A030701, A030702, A030704, A030705, A030706.

%K nonn,base

%O 1,3

%A _M. F. Hasler_, Sep 25 2011

%E Keyword:fini removed by _Jianing Song_, Jan 28 2023 as finiteness is only conjectured.