This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A213045 Number of (w,x,y) with all terms in {0,...,n} and 2|w-x|>max(w,x,y)-min(w,x,y). 3
 0, 4, 14, 36, 72, 128, 206, 312, 448, 620, 830, 1084, 1384, 1736, 2142, 2608, 3136, 3732, 4398, 5140, 5960, 6864, 7854, 8936, 10112, 11388, 12766, 14252, 15848, 17560, 19390, 21344, 23424, 25636, 27982, 30468, 33096, 35872, 38798, 41880 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Every term is even. a(n) + A087035(n+1) = (n+1)^3. LINKS Index entries for linear recurrences with constant coefficients, signature (3,-2,-2,3,-1). FORMULA a(n) = 3*a(n-1)-2*a(n-2)-2*a(n-3)+3*a(n-4)-a(n-5). G.f.: 2*x*(2 + x + x^2)/((-1 + x)^4*(1 + x)). a(n) = 2*A212685(n+1) = (2*n*(4*n^2+9*n+8)-3*(-1)^n+3)/12. [Bruno Berselli, Jun 11 2012] MATHEMATICA t = Compile[{{n, _Integer}}, Module[{s = 0}, (Do[If[Max[w, x, y] - Min[w, x, y] < 2 Abs[w - x],   s = s + 1], {w, 0, n}, {x, 0, n}, {y, 0, n}]; s)]]; m = Map[t[#] &, Range[0, 45]]   (* A213045 *) m/2  (* integers *) LinearRecurrence[{3, -2, -2, 3, -1}, {0, 4, 14, 36, 72}, 50] (* Harvey P. Dale, Jul 31 2013 *) CROSSREFS See A212959 for a guide to related sequences. Sequence in context: A295180 A305906 A177110 * A061989 A079908 A038164 Adjacent sequences:  A213042 A213043 A213044 * A213046 A213047 A213048 KEYWORD nonn,easy AUTHOR Clark Kimberling, Jun 10 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified April 18 14:35 EDT 2019. Contains 322209 sequences. (Running on oeis4.)