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A173962
Averages of two consecutive odd cubes; a(n) = (n^3+(n+2)^3)/2.
3
14, 76, 234, 536, 1030, 1764, 2786, 4144, 5886, 8060, 10714, 13896, 17654, 22036, 27090, 32864, 39406, 46764, 54986, 64120, 74214, 85316, 97474, 110736, 125150, 140764, 157626, 175784, 195286, 216180, 238514, 262336, 287694, 314636, 343210
OFFSET
1,1
COMMENTS
(1^3 + 3^3)/2 = 14,..
FORMULA
a(n) = 4*a(n-1)-6*a(n-2)+4*a(n-3)-a(n-4). - Colin Barker, Jan 17 2015
G.f.: 2*x*(7*x^2+10*x+7) / (x-1)^4. - Colin Barker, Jan 17 2015
MATHEMATICA
f[n_]:=(n^3+(n+2)^3)/2; Table[f[n], {n, 1, 6!, 2}]
Mean/@Partition[Range[1, 81, 2]^3, 2, 1] (* Harvey P. Dale, Apr 20 2015 *)
PROG
(PARI) Vec(2*x*(7*x^2+10*x+7)/(x-1)^4 + O(x^100)) \\ Colin Barker, Jan 17 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved