%I A080684
%S A080684 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,16,17,17,18,19,20,20,21,22,23,
%T A080684 24,25,25,26,26,27,28,28,29,30,30,30,31,32,32,33,33,34,35,35,35,36,37,
%U A080684 38,38,39,39,40,41,42,42,42,42,43,43,43,44,45,46,47,47,47,47,48,48,49
%N A080684 Number of 13-smooth numbers <= n.
%C A080684 Range = primes 2 to 13. Input pn=13 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 A080684 (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 A080684 Cf. A071520, A051038.
%Y A080684 Sequence in context: A057946 A117657 A106618 this_sequence A159062 A093616 
               A089247
%Y A080684 Adjacent sequences: A080681 A080682 A080683 this_sequence A080685 A080686 
               A080687
%K A080684 easy,nonn
%O A080684 1,2
%A A080684 Cino Hilliard (hillcino368(AT)gmail.com), Mar 02 2003