%I #6 May 22 2019 05:45:37
%S 2,61,521,61,23,61277761,821,61277761,23888027348153,4201,
%T 33670369817243,61277761,5265674839116110941,441435249928911950281,
%U 23888027348153,1232787935486158110509626783,270131
%N Smallest prime whose reversal is an n-th power.
%H Robert Israel, <a href="/A059004/b059004.txt">Table of n, a(n) for n = 1..271</a>
%p revdigs:= proc(n) local L,k;
%p L:= convert(n,base,10);
%p add(L[-k]*10^(k-1),k=1..nops(L))
%p end proc:
%p f:= proc(n) local d, k, wmin, v,w;
%p wmin:= infinity;
%p for d from 1 do
%p for k from ceil(10^(d/n)) do
%p v:= k^n;
%p if v >= 10^(d+1) then break fi;
%p w:= revdigs(v);
%p if isprime(w) and w < wmin then wmin:= w fi;
%p od;
%p if wmin < infinity then return wmin fi
%p od
%p end proc:
%p map(f, [$1..20]); # _Robert Israel_, May 22 2019
%t Do[ k = 1; While[ r = ToExpression[ StringReverse[ ToString[ k^n ] ] ]; ! PrimeQ[ r ], k++ ]; Print[ r ], {n, 1, 25} ]
%Y Cf. A007488.
%K nonn,base
%O 1,1
%A _Robert G. Wilson v_, Jan 16 2001