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

1,1

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).

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)

Prog

(Magma) [Floor((n+1/n)^3): n in [1..60]]
(PARI) a(n)=n^3+3*n+(3*n^2+1)\n^3 \\ Charles R Greathouse IV, Oct 07 2015

Crossrefs

Cf. A079908, A014052.

Sequence in context: A089954 A134020 A343141 * A306599 A226151 A253767

Adjacent sequences: A197599 A197600 A197601 * A197603 A197604 A197605

Keyword

nonn,easy

Author

Vincenzo Librandi, Oct 17 2011

Status

approved