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Number of integers k in [1,n] such that {n*r+k*r} > {n*r-k*r}, where { } = fractional part and r=sqrt(3).
2

%I #5 Mar 30 2012 18:57:44

%S 1,1,2,2,2,2,3,4,4,5,6,7,7,8,8,8,8,9,9,9,9,10,11,11,12,13,14,14,15,15,

%T 15,15,16,16,16,17,18,19,19,20,21,22,22,23,23,23,23,24,24,24,25,26,27,

%U 27,28,28,28,28,29,29,29,29,30,31,31,32,33,34,34,35,35,35,35

%N Number of integers k in [1,n] such that {n*r+k*r} > {n*r-k*r}, where { } = fractional part and r=sqrt(3).

%t r = Sqrt[3]; p[x_] := FractionalPart[x];

%t u[n_, k_] := If[p[n*r + k*r] <= p[n*r - k*r], 1, 0]

%t v[n_, k_] := If[p[n*r + k*r] > p[n*r - k*r], 1, 0]

%t s[n_] := Sum[u[n, k], {k, 1, n}]

%t t[n_] := Sum[v[n, k], {k, 1, n}]

%t Table[s[n], {n, 1, 100}] (* A194817 *)

%t Table[t[n], {n, 1, 100}] (* A194818 *)

%Y Cf. A194817, A194813.

%K nonn

%O 1,3

%A _Clark Kimberling_, Sep 03 2011