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A157728
a(n) = Fibonacci(n) - 4.
12
1, 4, 9, 17, 30, 51, 85, 140, 229, 373, 606, 983, 1593, 2580, 4177, 6761, 10942, 17707, 28653, 46364, 75021, 121389, 196414, 317807, 514225, 832036, 1346265, 2178305, 3524574, 5702883, 9227461, 14930348, 24157813, 39088165, 63245982, 102334151
OFFSET
5,2
COMMENTS
Partial sums of A071679. - R. J. Mathar, Oct 12 2010
FORMULA
From R. J. Mathar, Oct 12 2010: (Start)
a(n) = 2*a(n-1) - a(n-3).
G.f.: x^5*(1+x)^2/((x-1)*(x^2+x-1)). (End)
MATHEMATICA
Fibonacci[Range[5, 40]]-4 (* or *) LinearRecurrence[{2, 0, -1}, {1, 4, 9}, 40] (* Harvey P. Dale, Jan 17 2022 *)
PROG
(Magma) [ Fibonacci(n) - 4: n in [5..50] ]; // Vincenzo Librandi, Apr 24 2011
(Haskell)
a157728 = subtract 4 . a000045 -- Reinhard Zumkeller, Oct 31 2013
(PARI) a(n)=fibonacci(n) - 4 \\ Charles R Greathouse IV, Jun 11 2015
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Jun 26 2010
STATUS
approved