This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A141249 #2 Mar 30 2012 17:22:50 %S A141249 1,21,33,45,73,81,193,201,241,273,313,381,421,445,453,661,693,861,885, %T A141249 913 %N A141249 Numbers n such that the central point of the square n X n lattice sees the minimal number of points. %C A141249 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 A141249 Cf. A141226. %K A141249 nonn %O A141249 1,2 %A A141249 _T. D. Noe_, Jun 17 2008