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A074388 Solutions to sigma[2*(x^2)]=odd^2. 1

%I #5 Oct 15 2013 22:31:29

%S 195938,224450,13645088,15870978,18180450,29184800,1105252128,

%T 2363968800,2686005218,2917410498,3564550178,5056357922,8442721568,

%U 10814792450,18587462432,21292224800,48666384162,140836104992

%N Solutions to sigma[2*(x^2)]=odd^2.

%e m=195938=2.313.313 and sigma[195938]=294849=543.543 and 543=3.181 odd nonprime. No odd prime solutions were found below 10^12.

%t Do[s=DivisorSigma[1, 2*(n^2)]; If[IntegerQ[Sqrt[s]]&&Mod[s, 2]==1, Print[2*(n^2)]], {n, 1, 10000000}]

%Y Cf. A000203, A001248, A028982, A074386.

%K nonn

%O 1,1

%A _Labos Elemer_, Aug 22 2002

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Last modified March 29 01:36 EDT 2024. Contains 371264 sequences. (Running on oeis4.)