A376931 - OEIS

%I #22 Nov 22 2024 11:12:03

%S 0,0,1,0,2,2,3,0,5,4,5,4,6,6,9,0,8,10,9,8,13,10,11,8,14,12,16,12,14,

%T 18,15,0,21,16,23,20,18,18,25,16,20,26,21,20,33,22,23,16,27,28,33,24,

%U 26,32,37,24,37,28,29,36,30,30,47,0,44,42,33,32,45,46,35

%N Number of points out of n points placed on a circle that can never be reached when starting at one point and then moving clockwise in incrementally increasing steps (first 1, then 2, 3, 4, ...).

%C Put n distinct points on the edge of a circle. Connect the first to the point 1 step clockwise from it, then connect that one to the point 2 steps clockwise from that, continuing with 3 steps, 4 steps, etc. In the end, a(n) is the number of points never landed on.

%F a(n) = n - A117484(n).

%Y Cf. A117484.

%K nonn

%O 1,5

%A _Payton Richards_, Oct 11 2024