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%I #24 Sep 08 2022 08:45:51
%S 0,16,625,2401,14641,130321,1874161,12117361,104060401,1026625681,
%T 10098039121,100469346961,1036488922561,10106606869921,
%U 100091400875761,1011133218419041,10028029413722401,100004631514837921,1000534329357902641,10002039828958828561
%N a(n) = the smallest n-digit number with exactly 5 divisors, or 0 if no such number exists.
%C a(n) = the smallest n-digit number of the form p^4 (p = prime), a(n) = 0 if no such number exists.
%H Robert Israel, <a href="/A174336/b174336.txt">Table of n, a(n) for n = 1..999</a>
%F A000005(a(n)) = 5.
%p 0, seq(nextprime(floor(10^((n-1)/4)))^4, n=2..30); # _Robert Israel_, Dec 05 2016
%t Table[p=Ceiling[10^((n-1)/4)]; While[p^4<10^n && ! PrimeQ[p], p=NextPrime[p]]; If[p^4<10^n, p^4, 0], {n, 20}]
%o (Magma) [0] cat [NextPrime(Floor(10^((n-1)/4)))^4: n in [2..25]]; // _Vincenzo Librandi_, Dec 06 2016
%Y See A182647(n) - the largest n-digit number with exactly 5 divisors.
%K nonn,base
%O 1,2
%A _Jaroslav Krizek_, Nov 27 2010
%E Extended by _T. D. Noe_, Nov 29 2010
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