A211923 Number of (w,x,y,z) with all terms in {1,...,n} and 2*w*x>=3*y*z.

0, 0, 5, 31, 96, 238, 504, 921, 1585, 2560, 3896, 5698, 8113, 11165, 15042, 19860, 25733, 32814, 41320, 51271, 63015, 76686, 92385, 110397, 131022, 154298, 180579, 210119, 243109, 279810, 320658, 365615, 415291, 469881, 529582, 594834, 666111, 743335, 827162

Offset

0,3

Comments

a(n)+A211920(n)=n^4.

See A211795 for a guide to related sequences.

Links

Table of n, a(n) for n=0..38.

Mathematica

t = Compile[{{n, _Integer}}, Module[{s = 0},
(Do[If[2 w*x >= 3 y*z, s = s + 1],
{w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];
Map[t[#] &, Range[0, 40]] (* A211923 *)
(* Peter J. C. Moses, Apr 13 2012 *)

Crossrefs

Cf. A211795.

Sequence in context: A106909 A304659 A115519 * A362304 A024399 A183520

Adjacent sequences: A211920 A211921 A211922 * A211924 A211925 A211926

Keyword

nonn

Author

Clark Kimberling, Apr 28 2012

Status

approved