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A212055
Number of (w,x,y,z) with all terms in {1,...,n} and w*x<=y*z+2.
2
0, 1, 15, 62, 176, 395, 775, 1382, 2296, 3595, 5407, 7822, 10968, 14995, 20063, 26286, 33896, 43043, 53951, 66798, 81832, 99251, 119375, 142382, 168592, 198251, 231711, 269190, 311088, 357675, 409367, 466422, 529296, 598267, 673855
OFFSET
0,3
COMMENTS
a(n)+A212056(n)=n^4. See A211795 for a guide to related sequences.
MATHEMATICA
t = Compile[{{n, _Integer}}, Module[{s = 0},
(Do[If[w*x <= y*z + 2, s = s + 1],
{w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];
Map[t[#] &, Range[0, 50]] (* A212055 *)
(* Peter J. C. Moses, Apr 13 2012 *)
CROSSREFS
Cf. A211795.
Sequence in context: A157446 A220084 A240711 * A219296 A067572 A066584
KEYWORD
nonn
AUTHOR
Clark Kimberling, Apr 29 2012
STATUS
approved