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a(n) = floor(2^n/(-1 + cot(1/n))).
4

%I #4 Apr 06 2020 09:22:02

%S -6,4,4,5,8,12,21,36,64,114,205,373,684,1262,2344,4375,8202,15437,

%T 29155,55236,104940,199872,381551,729884,1398878,2685731,5164672,

%U 9946439,19181836,37039772,71608456,138593905,268520221,520756816,1010863710,1963933206

%N a(n) = floor(2^n/(-1 + cot(1/n))).

%F a(n) = floor(2^n/(-1 + cot(1/n))).

%t z = 50; u = Table[Floor[2^n/(1 - Cos[1/n])], {n, 1, z}] (* A332430 *)

%t v = Table[Floor[2^n/(-1 + Cot[1/n])], {n, 1, z}] (* A332431 *)

%t u - v (* A332432 *)

%t w = Table[Floor[2^n/(1 - Cos[1/n]) - 2^n/(-1 + Cot[1/n])], {n, 1, z}]

%t u - v - w (* A332479 *)

%Y Cf. A333186, A332430, A332432, A332433, A332479.

%K sign,easy

%O 1,1

%A _Clark Kimberling_, Apr 04 2020