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A171237 a(0)=2, a(1)=3, a(n) = 3 + a(n-1) + a(n-2) for n >= 2. 1
2, 3, 8, 14, 25, 42, 70, 115, 188, 306, 497, 806, 1306, 2115, 3424, 5542, 8969, 14514, 23486, 38003, 61492, 99498, 160993, 260494, 421490, 681987, 1103480, 1785470, 2888953, 4674426, 7563382, 12237811, 19801196, 32039010, 51840209, 83879222 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
a(n) gives the time complexity of a recursive Fibonacci algorithm.
LINKS
FORMULA
a(0)=2, a(1)=3, a(n) = 3 + a(n-1) + a(n-2) n >= 2.
From R. J. Mathar, Dec 06 2009: (Start)
a(n) = 2*a(n-1) - a(n-3) = A022095(n+1) - 3.
G.f.: (2-x+2*x^2)/((x-1)*(x^2+x-1)). (End)
MATHEMATICA
LinearRecurrence[{2, 0, -1}, {2, 3, 8}, 50] (* Harvey P. Dale, Mar 19 2020 *)
CROSSREFS
Sequence in context: A368855 A022951 A247124 * A173149 A128305 A328881
KEYWORD
nonn,easy
AUTHOR
Manfred Jackel (jkl(AT)uni-koblenz.de), Dec 05 2009
STATUS
approved

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Last modified February 23 14:24 EST 2024. Contains 370283 sequences. (Running on oeis4.)