%I A118310
%S A118310 1,2,3,4,1,2,1,2,3,2,1,4,1,2,3,1,1,9,1,10,1,11,1,1,1,2,3,4,1,2,1,2,3,1,
%T A118310 5,3,1,2,1,8,1,2,1,2,9,2,1,6,1,1,1,4,1,3,1,7,3,2,1,2,1,1,1,1,1,6,1,4,3,
%U A118310 2,1,24,1,1,25,2,1,3,1,4,1,1,1,6,5,2,3,2,1,30,1,2,3,2,5,6,1,1,1,4,1,2,
               1
%N A118310 a(n) = GCD(n,m(n)), where m(n) is the n-th nonprime positive integer 
               (1 or composite).
%C A118310 For n >= 1, a(n+1) = GCD(n+1,c(n)), where c(n) = the n-th composite.
%C A118310 First occurrence of k: 1, 2, 3, 4, 35, 48, 56, 40, 18, 20, 22, 120, 130, 
               140, 375, ..., . - Robert G. Wilson v.
%H A118310 Leroy Quet, <a href="http://www.prism-of-spirals.net/">Home Page</a> 
               (listed in lieu of email address)
%t A118310 NonPrime[n_Integer] := FixedPoint[n + PrimePi@# &, n + PrimePi@n]; f[n_] 
               := GCD[n, NonPrime@n]; Array[f, 103] - Robert G. Wilson v
%o A118310 (PARI) A002808(maxn)= { local(a); a=[4]; for(n=5,maxn, if( !isprime(n), 
               a=concat(a,n); ); ); return(a); } A118310(maxn)= { local(nonppo,a,
               newa,nonppol); a=[;]; nonppo=concat(1,A002808(maxn)); nonppol=matsize(nonppo); 
               for(n=1,nonppol[2], newa= gcd(n, nonppo[n]); a=concat(a,newa); ); 
               return(a); } print(A118310(180)); (Mathar)
%Y A118310 Cf. A064814.
%Y A118310 Sequence in context: A138297 A139458 A104412 this_sequence A073057 A084310 
               A078978
%Y A118310 Adjacent sequences: A118307 A118308 A118309 this_sequence A118311 A118312 
               A118313
%K A118310 nonn
%O A118310 1,2
%A A118310 Leroy Quet May 14 2006
%E A118310 More terms from Robert G. Wilson v (rgwv(at)rgwv.com) and R. J. Mathar 
               (mathar(AT)strw.leidenuniv.nl), May 16 2006