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Numbers that are the sum of two positive cubes in at least three ways (all solutions).
6

%I #24 Aug 28 2024 10:31:51

%S 87539319,119824488,143604279,175959000,327763000,700314552,804360375,

%T 958595904,1148834232,1407672000,1840667192,1915865217,2363561613,

%U 2622104000,3080802816,3235261176,3499524728,3623721192,3877315533,4750893000,5544709352,5602516416

%N Numbers that are the sum of two positive cubes in at least three ways (all solutions).

%D J. Leech, Some solutions of Diophantine equations, Proc. Camb. Phil. Soc., 53 (1957), 778-780.

%D R. K. Guy, Unsolved Problems in Number Theory, D1.

%H Ray Chandler, <a href="/A018787/b018787.txt">Table of n, a(n) for n=1..100000</a>

%H Uwe Hollerbach, <a href="http://www.korgwal.com/ramanujan/">Taxi, Taxi!</a> [Original link, broken]

%H Uwe Hollerbach, <a href="http://web.archive.org/web/20120203221114/http://www.korgwal.com/ramanujan">Taxi, Taxi!</a> [Replacement link to Wayback Machine]

%H Uwe Hollerbach, <a href="/A003825/a003825.html">Taxi! Taxi!</a> [Cached copy from Wayback Machine, html version of top page only]

%t a=Sort[Flatten@Table[n^3+m^3,{m,2000},{n,m-1,1,-1}]];f3[l_]:=Module[{t={}},Do[If[l[[n]]==l[[n+2]],AppendTo[t,l[[n]]]],{n,1,Length[l]-2}];t];f3[a] (* _Vladimir Joseph Stephan Orlovsky_, Jan 21 2012 *)

%Y Cf. A001235, A003825, A023051, A025294, A025398, A344804.

%K nonn

%O 1,1

%A _David W. Wilson_, Aug 15 1996