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%I #10 Aug 26 2015 00:56:51
%S 1,3,4,7,6,8,8,15,13,12,12,17,14,16,18,31,18,26,20,24,24,24,24,35,31,
%T 28,40,32,30,37,32,63,36,36,40,53,38,40,42,49,42,48,44,48,56,48,48,71,
%U 57,62,54,56,54,80,60,65,60,60,60,74,62,64,73,127,70,72,68,72,72,81,72,107
%N a(1) = 1; for n>=2, a(n) = n-th positive integer which is coprime to the largest prime divisor of n.
%F a(n)=A126572(A006530(n),n). - _R. J. Mathar_, Nov 09 2007
%e The largest prime dividing 12 is 3. The positive integers which are coprime to 3 are 1,2,4,5,7,8,10,11,13,14,16,17,19,20,... The 12th of these is 17, so a(12) = 17.
%p A126572 := proc(n,k) local f,i ; f := 1 ; for i from 1 do if gcd(i,n) = 1 then if f = k then RETURN(i) ; fi ; f := f+1 ; fi ; od: end: A006530 := proc(n) if n = 1 then 1; else max(seq(op(1,i),i=ifactors(n)[2]) ) ; fi ; end: A132009 := proc(n) local p ; p := A006530(n) ; A126572(p,n) ; end: seq(A132009(n),n=1..100) ; # _R. J. Mathar_, Nov 09 2007
%t a = {1}; For[n = 2, n < 70, n++, b = FactorInteger[n][[ -1, 1]]; c = 0; i = 1; While[c < n, If[GCD[i, b] == 1, c++ ]; i++ ]; AppendTo[a, i - 1]]; a (* _Stefan Steinerberger_, Nov 04 2007 *)
%K nonn
%O 1,2
%A _Leroy Quet_, Oct 29 2007
%E More terms from _Stefan Steinerberger_ and _R. J. Mathar_, Nov 04 2007
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