

A211812


Number of 4tuples (w,x,y,z) with all terms in {1,...,n} and w*x<=3*y*z.


2



0, 1, 15, 75, 224, 525, 1077, 1960, 3299, 5249, 7939, 11534, 16285, 22313, 29890, 39289, 50713, 64431, 80854, 100157, 122747, 148980, 179165, 213687, 253113, 297646, 347806, 404160, 467027, 536878, 614464, 700012, 794247, 897729
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,3


COMMENTS

See A211795 for a guide to related sequences.


LINKS



MATHEMATICA

t = Compile[{{n, _Integer}}, Module[{s = 0},
(Do[If[w*x <= 3 y*z, s = s + 1],
{w, 1, #}, {x, 1, #}, {y, 1, #}, {z, 1, #}] &[n]; s)]];
Map[t[#] &, Range[0, 40]] (* A211812 *)


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



