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%I #13 Apr 11 2021 00:00:54
%S 28,1225,16578,1479604544,1885800643779
%N Smallest number that is the sum of four positive n-th powers in three ways.
%H R. Alter, <a href="https://doi.org/10.1007/BFb0096461">Computations and generalizations on a remark of Ramanujan</a>, pp. 182-196 of "Analytic Number Theory (Philadelphia, 1980)", ed. M. I. Knopp, Lect. Notes Math., Vol. 899, 1981.
%e a(2) = 28 = 1+1+1+25 = 4+4+4+16 = 1+9+9+9.
%Y Cf. A230563, A342893-A342903.
%K nonn,more
%O 2,1
%A _N. J. A. Sloane_, Apr 04 2021
%E a(5)-a(6) from _Jinyuan Wang_, Apr 10 2021