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%I #8 Oct 06 2013 07:57:45
%S 11,2,3,41,5,23,7,181,19,251,0,43,0,127,53,281,0,29,0,541,37,0,0,83,
%T 11551,0,139,47,0,523,0,1481,0,0,157,149,0,0,0,12451,0,67,0,0,59,0,0,
%U 283,11177,2551,0,0,0,239,0,1187,0,0,0,1453,0,0,79,881,0,0,0,0,0,257,0
%N Smallest prime whose digital product = n or 0 if impossible.
%C Zeros appear at A068191.
%e a(20)=541 because 5*4*1=20 and there is no prime less than a(20) which exhibits this characteristic.
%t f[n_] := If[ Max[ First /@ FactorInteger[n]] > 7, 0, p = 1; While[Times @@ IntegerDigits[ Prime[p]] != n, p++ ]; Prime[p]]; Table[ f[n], {n, 30}]
%Y Cf. A004022, A107612, A107689, A107690, A107691, A107692, A107693, A107694, A107695, A107696, A107697.
%K base,nonn
%O 1,1
%A _Zak Seidov_ and _Robert G. Wilson v_, May 20 2005
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