A099958 (1/2)*number of distinct angular positions under which an observer positioned at the center of an edge of a square lattice can see the (2n)X(2n-1) points symmetrically surrounding his position.

1, 5, 13, 23, 37, 55, 75, 95, 127, 157, 185, 227, 263, 305, 357, 403, 455, 511, 571, 631, 703, 769, 833, 923, 997, 1069, 1169, 1245, 1329, 1443, 1535, 1631, 1743, 1849, 1957, 2075, 2195, 2307, 2439, 2565, 2683, 2845, 2957, 3097, 3265, 3385