%I A080685
%S A080685 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,18,19,20,21,21,22,23,24,
%T A080685 25,26,26,27,27,28,29,30,31,32,32,32,33,34,34,35,35,36,37,37,37,38,39,
%U A080685 40,41,42,42,43,44,45,45,45,45,46,46,46,47,48,49,50,50,51,51,52,52,53
%N A080685 Number of 17-smooth numbers <= n.
%C A080685 Range = primes 2 to 17. Input pn=17 in script below. Code below is much 
               faster than the code for cross-reference. For input of n=200 13 times 
               as fast and many times faster for larger input of n.
%o A080685 (PARI) smoothn(n,pn) = { for(m=1,n, pr=1; forprime(p=2,pn, pr*=p; ); 
               ct=1; for(x=1,m, f=0; forprime(y=nextprime(pn+1),floor(x), if(x%y 
               == 0,f=1; break) ); if(gcd(x,pr)<>1,if(f==0,ct+=1; )) ); print1(ct",
               "); ) }
%Y A080685 Cf. A071520, A051038.
%Y A080685 Sequence in context: A093616 A089247 A106620 this_sequence A074805 A121761 
               A056963
%Y A080685 Adjacent sequences: A080682 A080683 A080684 this_sequence A080686 A080687 
               A080688
%K A080685 easy,nonn
%O A080685 1,2
%A A080685 Cino Hilliard (hillcino368(AT)gmail.com), Mar 02 2003