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Numbers k such that k and R(k) both are squarefree where R(n) (A004086) is the digit reversal of n.
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%I #17 Sep 29 2023 12:00:42

%S 1,2,3,5,6,7,10,11,13,14,15,17,19,22,26,30,31,33,34,35,37,38,39,41,43,

%T 47,51,53,55,58,59,62,66,70,71,73,74,77,78,79,83,85,87,91,93,95,97,

%U 101,102,103,105,106,107,109,110,111,113,114,115,118,119,122,123,127,129

%N Numbers k such that k and R(k) both are squarefree where R(n) (A004086) is the digit reversal of n.

%H Harvey P. Dale, <a href="/A077337/b077337.txt">Table of n, a(n) for n = 1..1000</a>

%H Cécile Dartyge, Bruno Martin, Joël Rivat, Igor E. Shparlinski, and Cathy Swaenepoel, <a href="https://arxiv.org/abs/2309.11380">Reversible primes</a>, arXiv:2309.11380 [math.NT], 2023. See p. 6.

%t Select[Range[200],And@@SquareFreeQ/@{#,FromDigits[Reverse[ IntegerDigits[ #]]]}&] (* _Harvey P. Dale_, Jan 04 2014 *)

%t Select[Range[200],AllTrue[{#,IntegerReverse[#]},SquareFreeQ]&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Dec 16 2018 *)

%Y Cf. A004086, A005117.

%K base,easy,nonn,less

%O 1,2

%A _Amarnath Murthy_, Nov 04 2002

%E More terms from _David Wasserman_, Oct 25 2006