A141249 - OEIS

%I #2 Mar 30 2012 17:22:50

%S 1,21,33,45,73,81,193,201,241,273,313,381,421,445,453,661,693,861,885,

%T 913

%N Numbers n such that the central point of the square n X n lattice sees the minimal number of points.

%C These n are the numbers for which A141248(n) is odd. Note that n must be odd. When A141248(n)=1, the central point is the only point seeing the minimal number of points. These numbers are 1 or 9 (mod 12). These numbers also seem to produce cubic n X n X n lattices in which the central point has minimal visibility. Note that for n>1, n+1 is twice a prime power in A141250.

%Y Cf. A141226.

%K nonn

%O 1,2

%A _T. D. Noe_, Jun 17 2008