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 A100701 a(n) = a(n-1) + a(n-2) + a(n-1)*a(n-2) for n>=2; a(0)=2, a(1)=3. 1
 2, 3, 11, 47, 575, 27647, 15925247, 440301256703, 7011906707722862591, 3087351335301583621409910816767, 21648219537098310851336266290644502090473753542655 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS In general, if b(n) is defined recursively by b(0) = p, b(1) = q, b(n) = b(n-1) + b(n-2) + b(n-1) * b(n-2) for n >= 2 then b(n) = p^Fibonacci(n-1) * q^Fibonacci(n) - 1. - Rahul Goswami, Apr 15 2020 LINKS FORMULA a(n) = a(n-1) + a(n-2) + a(n-1)*a(n-2) with a(0)=2 and a(1)=3. a(n) = 3^Fibonacci(n-1) * 4^Fibonacci(n) - 1. - Rahul Goswami, Apr 15 2020 EXAMPLE a(2) = (2 + 3) + 2*3 = 11. MATHEMATICA a=2; b=3; lst={a, b}; Do[c=a*b+a+b; AppendTo[lst, c]; a=b; b=c, {n, 2*3!}]; lst (* Vladimir Joseph Stephan Orlovsky, Sep 05 2009 *) PROG (PARI) a(n)={3^fibonacci(n-1) * 4^fibonacci(n) - 1} \\ Andrew Howroyd, Apr 14 2020 CROSSREFS Cf. A000045 (Fibonacci), A063896. Sequence in context: A287060 A041345 A268285 * A011365 A072876 A184315 Adjacent sequences:  A100698 A100699 A100700 * A100702 A100703 A100704 KEYWORD nonn AUTHOR Parthasarathy Nambi, Dec 09 2004 EXTENSIONS More terms from Vladimir Joseph Stephan Orlovsky, Sep 05 2009 STATUS approved

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Last modified August 6 19:52 EDT 2020. Contains 336256 sequences. (Running on oeis4.)