|
|
A212752
|
|
Number of (w,x,y,z) with all terms in {0,...,n} and at least one of these conditions holds: w<R, x<R, y<R, z>R, where R=max{w,x,y,z}-min{w,x,y,z}.
|
|
2
|
|
|
0, 14, 71, 238, 580, 1224, 2265, 3896, 6236, 9550, 13975, 19854, 27336, 36848, 48545, 62944, 80200, 100926, 125271, 153950, 187100, 225544, 269401, 319608, 376260, 440414, 512135, 592606, 681856, 781200, 890625, 1011584, 1144016
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
COMMENTS
|
For a guide to related sequences, see A211795.
|
|
LINKS
|
|
|
FORMULA
|
a(n)=2*a(n-1)+2*a(n-2)-6*a(n-3)+6*a(n-5)-2*a(n-6)-2*a(n-7)+a(n-8).
G.f.: -x*(14+43*x+68*x^2+46*x^3+14*x^4+x^5) / ( (1+x)^3*(x-1)^5 )
|
|
MATHEMATICA
|
t = Compile[{{n, _Integer}},
Module[{s = 0}, (Do[If[(w < # || x < # || y < # || z > #) &[Max[w, x, y, z] - Min[w, x, y, z]], s++],
{w, 0, n}, {x, 0, n}, {y, 0, n}, {z, 0, n}]; s)]];
Map[t[#] &, Range[0, 40]] (* A212752 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|