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A211263 Number of integer pairs (x,y) such that 0 and x*y=floor(n/2).

%I A211263 #4 Apr 11 2012 18:49:18
%S A211263 0,0,0,1,1,1,1,1,1,1,1,2,2,1,1,2,2,1,1,2,2,1,1,3,3,1,1,2,2,2,2,2,2,1,
%T A211263 1,3,3,1,1,3,3,2,2,2,2,1,1,4,4,1,1,2,2,2,2,3,3,1,1,4,4,1,1,3,3,2,2,2,
%U A211263 2,2,2,4,4,1,1,2,2,2,2,4,4,1,1,4,4,1,1,3,3,3,3,2,2,1,1,5,5,1,1
%N A211263 Number of integer pairs (x,y) such that 0<x<y<=n and x*y=floor(n/2).
%C A211263 For a guide to related sequences, see A211266.
%e A211263 a(12) counts these pairs: (1,6) and (2,3).
%t A211263 a = 1; b = n; z1 = 120;
%t A211263 t[n_] := t[n] = Flatten[Table[x*y, {x, a, b - 1},
%t A211263  {y, x + 1, b}]]
%t A211263 c[n_, k_] := c[n, k] = Count[t[n], k]
%t A211263 Table[c[n, n], {n, 1, z1}]           (* A056924 *)
%t A211263 Table[c[n, n + 1], {n, 1, z1}]       (* A211159 *)
%t A211263 Table[c[n, 2*n], {n, 1, z1}]         (* A211261 *)
%t A211263 Table[c[n, 3*n], {n, 1, z1}]         (* A211262 *)
%t A211263 Table[c[n, Floor[n/2]], {n, 1, z1}]  (* A211263 *)
%t A211263 Print
%t A211263 c1[n_, m_] := c1[n, m] = Sum[c[n, k], {k, a, m}]
%t A211263 Table[c1[n, n], {n, 1, z1}]          (* A211264 *)
%t A211263 Table[c1[n, n + 1], {n, 1, z1}]      (* A211265 *)
%t A211263 Table[c1[n, 2*n], {n, 1, z1}]        (* A211266 *)
%t A211263 Table[c1[n, 3*n], {n, 1, z1}]        (* A211267 *)
%t A211263 Table[c1[n, Floor[n/2]], {n, 1, z1}] (* A181972 *)
%Y A211263 Cf. A211266.
%K A211263 nonn
%O A211263 1,12
%A A211263 _Clark Kimberling_, Apr 06 2012