%I A072178
%S A072178 4,19,21,24,44,42,50,57,0,60,76,91,56,86,85,66,92,88,114,129,131,106,
%T A072178 130,122,117,157,134,175,119,150,181,165,185,179,198,182,220,228,188,
%U A072178 190,261,235,222,231,229,233,224,227,288,372,241,279,254,253,318,267
%N A072178 a(n)-th factorial is the smallest factorial containing exactly n 4's, 
               or 0 if no such number exists.
%C A072178 It is conjectured that a(9)=0 since no factorial < 10000 contained just 
               9 fours.
%e A072178 a(2)=19 since 19-th factorial i.e. 19!=121645100408832000 contains exactly 
               two 4's.
%t A072178 Do[k = 1; While[ Count[IntegerDigits[k! ], 4] != n, k++ ]; Print[k], 
               {n, 1, 60}]
%Y A072178 Cf. A072244, A072220, A072208, A072204, A072200, A072199, A072177, A072163 
               & A072124.
%Y A072178 Sequence in context: A165820 A043056 A012879 this_sequence A116980 A022135 
               A028564
%Y A072178 Adjacent sequences: A072175 A072176 A072177 this_sequence A072179 A072180 
               A072181
%K A072178 base,nonn
%O A072178 1,1
%A A072178 Shyam Sunder Gupta (guptass(AT)rediffmail.com), Jul 30 2002
%E A072178 Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Jul 31 
               2002