%I #7 Dec 05 2013 19:55:07
%S 1,2,6,38,358,2589,25789,257889,2578899,45578899,45578899,556788899,
%T 556788899,25567788899,455577888999,5557788888999,5557788888999,
%U 255577888889999,255577888889999,5555778888889999,355557778888889999
%N a(n) = smallest number whose digit product equals n!/m where m is the product of all prime factors > 7 of n! (with multiplicity).
%e For n = 12 we have n! = 479001600, m = 11 and n!/m = 43545600 = 5*5*6*7*8*8*8*9*9, so a(12) = 556788899.
%o (PARI) {for(n=1,21,f=factor(n!); m=1; for(j=1,matsize(f)[1],if(f[j,1]<=7,m=m*f[j,1]^f[j,2])); s=if(m>1,"","1"); k=9; while(m>1,d=divrem(m,k); if(d[2]==0,s=concat(k,s); m=d[1],k--)); print1(eval(s),","))}
%K easy,nonn,base
%O 1,2
%A _Amarnath Murthy_, Jan 07 2002
%E Edited, corrected and extended by _Klaus Brockhaus_, Jun 17 2003