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Least positive number having exactly n partitions into three squares.
5

%I #7 Dec 26 2012 11:18:11

%S 1,9,41,81,146,194,306,369,425,594,689,866,1109,1161,1154,1361,1634,

%T 1781,1889,2141,2729,2609,3626,3366,3566,3449,3506,4241,4289,4826,

%U 5066,5381,7034,5561,6254,7229,7829,8186,8069,8126,8609,8921,8774,10386

%N Least positive number having exactly n partitions into three squares.

%C Note that a square can be zero.

%H Vincenzo Librandi, <a href="/A095809/b095809.txt">Table of n, a(n) for n = 1..200</a>

%e 41 is the least number having three partitions: 41 = 0+16+25 = 1+4+36 = 9+16+16.

%t lim=200; nLst=Table[0, {lim^2}]; Do[n=a^2+b^2+c^2; If[n>0 && n<lim^2, nLst[[n]]++ ], {a, 0, lim}, {b, a, Sqrt[lim^2-a^2]}, {c, b, Sqrt[lim^2-a^2-b^2]}]; u=Union[nLst]; kMax=First[Complement[1+Range[u[[ -1]]], u]]-1; Table[First[Flatten[Position[nLst, k]]], {k, kMax}]

%Y Apart from initial term, same as A000437.

%Y Cf. A094739 (n having a unique partition into three squares), A095811 (greatest number having exactly n partitions into three squares).

%K nonn

%O 1,2

%A _T. D. Noe_, Jun 07 2004