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%I #11 Oct 11 2019 12:37:39
%S 0,1,1,3,3,9,14,31,43,69,76,118,141,206,235,280,331,440,493,637,704,
%T 829,926,1152,1247,1470,1613,1841,1996,2375,2494,2932,3144,3428,3656,
%U 4032,4216,4824,5122,5544,5820,6582,6802,7647,8000,8451,8870,9850,10159
%N a(0)=0. a(n) = a(n-1) + (sum of positive integers which are coprime to n, <= n and missing from {a(0),a(1),a(2),..,a(n-1)}).
%e The positive integers which are coprime to 8 and <= 8 are 1,3,5,7. Of these, 5 and 7 are missing from the terms a(0) through a(7). So a(8) = a(7) + 5 + 7 = 43.
%t f[l_List] := Block[{n = Length[l]},Append[l, l[[ -1]] + Plus @@ Select[Range[n], GCD[n, # ] == 1 && FreeQ[l, # ] &]]];Nest[f, {0}, 50] (* _Ray Chandler_, Oct 26 2006 *)
%t s={0,1}; b=1; Do[ b=b+Total[ Select[ Range[ n ],GCD[ #1,n ]==1&&FreeQ[ s,#1 ]& ] ]; AppendTo[ s,b ],{n,2,100} ]; s (*Seidov*)
%Y Cf. A122965.
%K nonn
%O 0,4
%A _Leroy Quet_, Oct 23 2006
%E Extended by _Ray Chandler_ and _Zak Seidov_, Oct 26 2006
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