%I A118783
%S A118783 1,2,4,3,8,5,12,9,13,11,19,15,23,21,20,25,32,18,35,24,30,29,43,28,41,37,
%T A118783 44,38,55,27,60,47,49,51,56,42,71,54,61,50,79,46,83,63,65,68,91,59,87,
%U A118783 67,81,75,104,66,93,77,88,85,115,57,119,96,90,99,109,73,131,102,105,80
%N A118783 a(1) = 1. a(n) = (number of earlier terms of the sequence which are coprime 
               to n)th positive integer not among the earlier terms of the sequence.
%H A118783 Leroy Quet, <a href="http://www.prism-of-spirals.net/">Home Page</a> 
               (listed in lieu of email address)
%e A118783 The first 7 terms of the sequence are 1,2,4,3,8,5,12. Of these there 
               are 3 terms that are coprime to 8 (those terms being 1, 3 and 5). 
               So a(8) is the 3rd positive integer missing from the first 7 terms 
               of the sequence (i.e. is the 3rd integer of the sequence 6, 7, 9, 
               10, 11, 13,..). So a(8) = 9.
%o A118783 Contribution from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jul 
               30 2009: (Start)
%o A118783 (MAGMA) find:=function(S, k) c:=0; j:=0; while j lt #S and c lt k do 
               j+:=1; if S[j] eq 0 then c+:=1; end if; end while; if c eq k then 
               return j; else return 0; end if; end function;
%o A118783 z:=150; m:=70; W:=[ 0: n in [1..z] ]; V:=[1]; W[1]:=1; for n in [2..m] 
               do c:=#[ j: j in [1..#V] | Gcd(n, V[j]) eq 1 ]; a:=find(W, c); if 
               a eq 0 then break; end if; W[a]:=1; Append(~V, a); end for; print 
               V; (End)
%Y A118783 Cf. A118784.
%Y A118783 Sequence in context: A131395 A109812 A137622 this_sequence A120242 A054427 
               A048672
%Y A118783 Adjacent sequences: A118780 A118781 A118782 this_sequence A118784 A118785 
               A118786
%K A118783 nonn
%O A118783 1,2
%A A118783 Leroy Quet Apr 29 2006
%E A118783 Extended by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jul 30 
               2009