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A330650 Terms of A330606 which are not squares or powers of 2. 1


%S 1250,4802,31250,57122,167042,235298,260642,320000,559682,941192,

%T 1229312,1414562,3001250,3543122,3748322,5120000,6837602,8000000,

%U 9653618,9759362,14172488,14623232,15059072,15780962,19531250,19668992,24234722,35701250,38614472,40302242

%N Terms of A330606 which are not squares or powers of 2.

%H Giovanni Resta, <a href="/A330650/b330650.txt">Table of n, a(n) for n = 1..655</a> (terms < 10^13, first 155 terms from Amiram Eldar and Robert G. Wilson v)

%t fQ[n_] := CoprimeQ[n*DivisorSigma[0, n], DivisorSigma[1, n]] && !IntegerQ@ Sqrt@ n && !IntegerQ@ Log2@ n; Select[Range[10^6], fQ@# &]

%o (MAGMA) [k:k in [1..10000000]|Gcd(k*NumberOfDivisors(k), DivisorSigma(1, k)) eq 1 and (not IsSquare(k)) and (not IsIntegral(Log(2,k)))]; // _Marius A. Burtea_, Dec 23 2019

%Y Cf. A330606.

%K nonn

%O 1,1

%A _Amiram Eldar_ and _Robert G. Wilson v_, Dec 22 2019

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Last modified September 18 04:22 EDT 2021. Contains 347508 sequences. (Running on oeis4.)