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%I #17 Jul 23 2024 10:49:49
%S 1,2,2,4,5,5,7,7,8,10,11,11,13,13,14,16,17,17,19,19,20,22,23,23,25,25,
%T 26,28,29,29,31,31,32,34,35,35,37,37,38,40,41,41,43,43,44,46,47,47,49,
%U 49,50,52,53,53,55,55,56,58,59,59,61,61,62,64,65,65,67,67,68,70,71,71
%N a(n) = largest integer <= n which is coprime to A118002(n-1). a(n) = A118002(n) - A118002(n-1).
%p A118002 := proc(nmax) local a,n ; a := [0] ; while nops(a) < nmax do n := nops(a) ; while gcd(n,op(-1,a)) <> 1 do n := n-1 ; od ; a := [op(a), op(-1,a)+n] ; od ; RETURN(a) ; end: a118002 := A118002(100) : for n from 1 to nops(a118002)-1 do printf("%d, ",op(n+1,a118002)-op(n,a118002)) ; od ; # _R. J. Mathar_, Jun 06 2007
%t A118002[n_] := A118002[n] = If[n == 0, 0, Module[{a1 = A118002[n-1], k}, For[k = n, True, k--, If[CoprimeQ[a1, k], Return[a1+k]]]]];
%t a[n_] := A118002[n] - A118002[n-1];
%t Table[a[n], {n, 1, 72}] (* _Jean-François Alcover_, Apr 08 2024 *)
%Y Cf. A118001, A118002.
%K nonn
%O 1,2
%A _Leroy Quet_, Apr 09 2006
%E More terms from _R. J. Mathar_, Jun 06 2007
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