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a(n) = the maximum number of lattice points touched by an origin-centered sphere with radius <= n.
5

%I #5 Oct 19 2017 03:14:02

%S 6,12,30,48,48,72,96,96,120,144,168,168,192,240,240,240,264,312,336,

%T 336,336,384,384,384,408,432,480,480,504,528,552,552,552,672,672,696,

%U 720,720,720,720,768,768,816,864,864,864,936,936,936,936,936,1008,1008

%N a(n) = the maximum number of lattice points touched by an origin-centered sphere with radius <= n.

%F a(n) = max(i=0 to n^2) A005875(i)

%e a(4 to 5)=48 because the sphere with radius sqrt(14) touches 48 lattice points; but no sphere touches more, until the radius is sqrt(26).

%o (FORTRAN) See A071339.

%Y Cf. A005875, A071339-A071347.

%K easy,nonn

%O 1,1

%A _Hugo Pfoertner_, May 22 2002

%E Edited by _Don Reble_, Nov 06 2005