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%I #19 May 16 2021 01:48:53
%S 2056364173794800,12191487610289536,263214614245734400,
%T 696885239160606459,1560510414117060608,4497268448089227600,
%U 18896044524917750533,25704745581139341318,26662783403703215232,33691470623454003200,44053472466326057527,100502405478837434259
%N Numbers that are the sum of four positive seventh powers in two or more ways.
%H D. J. Bernstein, <a href="http://pobox.com/~djb/papers/sortedsums.dvi">Enumerating solutions to p(a) + q(b) = r(c) + s(d)</a>
%H R. L. Ekl, <a href="http://dx.doi.org/10.1090/S0025-5718-98-00979-X">New Results in Equal Sums of Like Powers</a>, Math. Comput. 67, 1309-1315, 1998.
%e 4497268448089227600 = 30^7 + 42^7 + 369^7 + 447^7 = 45^7 + 270^7 + 387^7 + 438^7. - _Sean A. Irvine_, May 15 2021
%Y Cf. A025367, A025406, A309763.
%K nonn,hard
%O 1,1
%A _N. J. A. Sloane_
%E Corrected by D. J. Bernstein (djb(AT)cr.yp.to)
%E a(6)-a(12) from _Sean A. Irvine_, May 14 2021
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