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A225983
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Numbers k such that gcd(phi(k), tau(k)) = 1.
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3
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1, 2, 4, 16, 25, 64, 81, 100, 121, 256, 289, 484, 529, 729, 841, 1024, 1156, 1296, 1600, 1681, 2116, 2209, 2401, 2809, 3025, 3364, 3481, 4096, 4624, 5041, 5184, 6400, 6724, 6889, 7225, 7744, 7921, 8464, 8836, 10201, 11236, 11449, 11664, 12100, 12769, 13225
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OFFSET
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1,2
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LINKS
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EXAMPLE
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If n = 13924 then phi(n) = 6844 = 2^2*29*59 and tau(n) = 9 = 3^2. There is no common prime factor.
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MAPLE
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with(numtheory); A225983:=proc(q) local n;
for n from 1 to q do if gcd(tau(n), phi(n))=1 then print(n);
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MATHEMATICA
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t = {}; n = 0; While[Length[t] < 100, n++; If[GCD[EulerPhi[n], DivisorSigma[0, n]] == 1, AppendTo[t, n]]]; t (* T. D. Noe, May 22 2013 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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