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A212890
Number of (w,x,y,z) with all terms in {0,...,n} and odd range.
3
0, 14, 28, 152, 276, 702, 1128, 2144, 3160, 5150, 7140, 10584, 14028, 19502, 24976, 33152, 41328, 52974, 64620, 80600, 96580, 117854, 139128, 166752, 194376, 229502, 264628, 308504, 352380, 406350, 460320, 525824, 591328, 669902
OFFSET
0,2
COMMENTS
a(n) + A212889(n) = (n+1)^4.
For a guide to related sequences, see A211795.
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.: f(x)/g(x), where f(x)=-7*x-34*x^3-7*x^5 and g(x)=((-1+x)^5)*(1+x)^3.
MATHEMATICA
t = Compile[{{n, _Integer}}, Module[{s = 0}, (Do[If[(Mod[#, 2] == 1) &[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]] (* A212890 *)
%/2 (* integers *)
CROSSREFS
Sequence in context: A077265 A033847 A067295 * A019552 A325728 A305662
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, May 30 2012
STATUS
approved