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%I #10 Apr 10 2021 09:18:52
%S 5978882,236674,20995,6626,2925,2925,2854,1620,1621,777,778,779,780,
%T 781,782,528,529,515,516,517,518,519,520,521,522,523,524,525,526,512,
%U 513,514,515,516,517,518,519,520,521,522,523,524,525,526,527,528,529,530,531
%N a(n) is the smallest number that is the sum of n positive 4th powers in four ways.
%C This is r(n,4,4) in Alter's notation.
%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. See Table 12, page 194.
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).
%F a(n) = n + 480 for n >= 32.
%e a(3) = 5978882 = 3^4 + 40^4 + 43^4 = 8^4 + 37^4 + 45^4 = 15^4 + 32^4 + 47^4 = 23^4 + 25^4 + 48^4.
%e a(4) = 236674 = 1^4 + 2^4 + 7^4 + 22^4 = 3^4 + 6^4 + 18^4 + 19^4 = 7^4 + 14^4 + 16^4 + 19^4 = 8^4 + 16^4 + 17^4 + 17^4.
%Y Cf. A085559, A123075, A342897, A343077, A343082, A343084, A343085.
%K nonn
%O 3,1
%A _Sean A. Irvine_, Apr 04 2021