cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A063831 Sum of cubes of divisors is a square.

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%I A063831 #19 Dec 06 2018 12:13:00
%S A063831 1,2,345,690,47196,46248900,53262468,71315748,140553735,188194335,
%T A063831 215515727,281107470,288564647,292978595,310129096,376388670,
%U A063831 431031454,577129294,585957190,1474108335,2133051720,2489605188,2948216670,3270679304,4043104611,5142743032
%N A063831 Sum of cubes of divisors is a square.
%e A063831 345 is in the sequence since sigma_3(345) = 6552^2 is a square.
%t A063831 Select[Range[10^5], IntegerQ[ Sqrt[ DivisorSigma[3,#] ] ] &] (* _Amiram Eldar_, Dec 06 2018 *)
%o A063831 (PARI) for(n=1,10^5, if(issquare(sigma(n,3)),print1(n, ", ")))
%Y A063831 Cf. A001158, A006532, A046655.
%K A063831 nonn
%O A063831 1,2
%A A063831 _Jason Earls_, Aug 21 2001
%E A063831 More terms from _Thomas Baruchel_, Oct 20 2003
%E A063831 More terms from _Sean A. Irvine_, Sep 24 2009
%E A063831 a(24)-a(26) from _Amiram Eldar_, Dec 06 2018