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A022371
Fibonacci sequence beginning 2, 18.
2
2, 18, 20, 38, 58, 96, 154, 250, 404, 654, 1058, 1712, 2770, 4482, 7252, 11734, 18986, 30720, 49706, 80426, 130132, 210558, 340690, 551248, 891938, 1443186, 2335124, 3778310, 6113434, 9891744, 16005178
OFFSET
0,1
FORMULA
G.f.: (2+16*x)/(1-x-x^2). - Philippe Deléham, Nov 19 2008
a(n) = 2*(Fibonacci(n+2) + 7*Fibonacci(n)). - G. C. Greubel, Aug 27 2017
a(n) = 2 * A022099(n). - Alois P. Heinz, Aug 27 2017
MATHEMATICA
a={}; b=2; c=18; AppendTo[a, b]; AppendTo[a, c]; Do[b=b+c; AppendTo[a, b]; c=b+c; AppendTo[a, c], {n, 4!}]; a (* Vladimir Joseph Stephan Orlovsky, Sep 18 2008 *)
Transpose[NestList[{Last[#], Total[#]}&, {2, 18}, 30]][[1]] (* Harvey P. Dale, Apr 13 2011 *)
LinearRecurrence[{1, 1}, {2, 18}, 40] (* Harvey P. Dale, Jun 26 2021 *)
PROG
(PARI) for(n=0, 50, print1(2*(fibonacci(n+2) + 7*fibonacci(n)), ", ")) \\ G. C. Greubel, Aug 27 2017
CROSSREFS
Cf. A022099.
Sequence in context: A231502 A231864 A066242 * A299380 A352159 A266956
KEYWORD
nonn
STATUS
approved