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 A063831 Sum of cubes of divisors is a square. 0

%I

%S 1,2,345,690,47196,46248900,53262468,71315748,140553735,188194335,

%T 215515727,281107470,288564647,292978595,310129096,376388670,

%U 431031454,577129294,585957190,1474108335,2133051720,2489605188,2948216670,3270679304,4043104611,5142743032

%N Sum of cubes of divisors is a square.

%e 345 is in the sequence since sigma_3(345) = 6552^2 is a square.

%t Select[Range[10^5], IntegerQ[ Sqrt[ DivisorSigma[3,#] ] ] &] (* _Amiram Eldar_, Dec 06 2018 *)

%o (PARI) for(n=1,10^5, if(issquare(sigma(n,3)),print1(n, ", ")))

%Y Cf. A001158, A006532, A046655.

%K nonn

%O 1,2

%A _Jason Earls_, Aug 21 2001

%E More terms from _Thomas Baruchel_, Oct 20 2003

%E More terms from _Sean A. Irvine_, Sep 24 2009

%E a(24)-a(26) from _Amiram Eldar_, Dec 06 2018

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Last modified April 6 21:24 EDT 2020. Contains 333286 sequences. (Running on oeis4.)