%I #10 Apr 03 2012 14:53:31
%S 0,24,102,1001,10002,100006,1000002,10000005,100000006,1000000003,
%T 10000000001,100000000006,1000000000001,10000000000001,
%U 100000000000018,1000000000000002,10000000000000006,100000000000000007,1000000000000000001
%N a(n) = the smallest n-digit number with exactly 8 divisors, a(n) = 0 if no such number exists.
%C a(n) = the smallest n-digit number of the form p^7, p^3*q or p*q*r (p, q, r = distinct primes), a(n) = 0 if no such number exists.
%F a(n) = min {10^(n-1) <= k < 10^n : A000005(k)=8} if set is nonempty, else a(n) = 0.
%p with (numtheory):
%p a:= proc(n) local k;
%p if n<2 then 0
%p else for k from 10^(n-1) while tau(k)<>8
%p do od; k
%p fi
%p end:
%p seq (a(n), n=1..20);
%Y Cf. A000005, A182676, A180922.
%K nonn,base
%O 1,2
%A _Jaroslav Krizek_, Nov 27 2010
%E Edited by _Alois P. Heinz_, Nov 27 2010
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