A197602 Floor((n+1/n)^3).
8, 15, 37, 76, 140, 234, 364, 536, 756, 1030, 1364, 1764, 2236, 2786, 3420, 4144, 4964, 5886, 6916, 8060, 9324, 10714, 12236, 13896, 15700, 17654, 19764, 22036, 24476, 27090, 29884, 32864, 36036, 39406, 42980, 46764, 50764, 54986, 59436, 64120, 69044, 74214, 79636, 85316, 91260, 97474, 103964, 110736, 117796, 125150
Offset: 1
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..10000
- Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
Programs
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Magma
[Floor((n+1/n)^3): n in [1..60]]
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PARI
a(n)=n^3+3*n+(3*n^2+1)\n^3 \\ Charles R Greathouse IV, Oct 07 2015
Formula
From Bruno Berselli, Oct 17 2011: (Start)
G.f.: x*(8-17*x+25*x^2-14*x^3+6*x^4-3*x^5+x^6)/(1-x)^4.
a(n) = 4*a(n-1)-6*a(n-2)+4*a(n-3)-a(n-4) for n>7.
a(n) = A079908(n) for n>3. (End)