A212054 Number of (w,x,y,z) with all terms in {1,...,n} and w*x>y*z+1.

0, 0, 3, 25, 98, 260, 571, 1089, 1898, 3084, 4755, 7017, 9994, 13836, 18691, 24705, 32066, 40964, 51579, 64145, 78850, 95956, 115723, 138385, 164170, 193436, 226467, 263521, 304930, 351076, 402195, 458777, 521082, 589532, 664547

Offset

0,3

Comments

a(n)+A212053(n)=n^4. See A211795 for a guide to related sequences.

Links

Table of n, a(n) for n=0..34.

Mathematica

t = Compile[{{n, _Integer}}, Module[{s = 0},
(Do[If[w*x > y*z + 1, s = s + 1],
{w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];
Map[t[#] &, Range[0, 50]] (* A212054 *)
(* Peter J. C. Moses, Apr 13 2012 *)

Crossrefs

Cf. A211795.

Sequence in context: A114378 A075306 A183761 * A180324 A124245 A360788

Adjacent sequences: A212051 A212052 A212053 * A212055 A212056 A212057

Keyword

nonn

Author

Clark Kimberling, Apr 29 2012

Status

approved