|
%I #10 Apr 10 2021 09:20:27
%S 325,54,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,
%T 48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,
%U 71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90
%N a(n) is the smallest number that is the sum of n positive squares in three ways.
%C This is r(n,2,3) 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 6, page 191.
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).
%F a(n) = n + 24 for n >= 4.
%e a(2) = 325 = 1^2 + 18^2 = 6^2 + 17^2 = 10^2 + 15^2.
%e a(3) = 54 = 1^2 + 2^2 + 7^2 = 2^2 + 5^2 + 5^2 = 3^2 + 3^2 + 6^2.
%Y Cf. A342902, A343083, A343081, A343082, A343083, A343084.
%K nonn
%O 2,1
%A _Sean A. Irvine_, Apr 04 2021
|
