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A273397 a(n) = Fibonacci(Catalan(n)). 3

%I #21 Jan 21 2017 19:01:45

%S 1,1,1,5,377,267914296,1725375039079340637797070384,

%T 202401005213503038261932567177107618332887918916819829782797456368284639448671475316218754

%N a(n) = Fibonacci(Catalan(n)).

%C Next term, a(8), which has 299 digits, is too large to include. Counterpart to A273398.

%C The number of digits of a(n) grows faster than Fibonacci(n), in contrast to A273398, and faster than Catalan(n-2), but slower than Catalan(n-1) or Catalan(n).

%H Alois P. Heinz, <a href="/A273397/b273397.txt">Table of n, a(n) for n = 0..8</a>

%F a(n) = A000045(A000108(n)).

%e For n = 3, a(3) = Fibonacci(Catalan(3)) = Fibonacci(5) = 5.

%p a:= n-> (<<0|1>, <1|1>>^(binomial(2*n, n)/(n+1)))[1, 2]:

%p seq(a(n), n=0..8); # _Alois P. Heinz_, Jan 20 2017

%t Fibonacci[CatalanNumber[Range[0, 7]]]

%o (PARI) for(n=0,7, cn=binomial(2*n, n)/(n+1); print1(fibonacci(cn) ","))

%Y Cf. A000045 (Fibonacci), A000108(Catalan), A263986, A273398 (related sequences with Fibonacci and Catalan numbers), A281450.

%K nonn,easy

%O 0,4

%A _Waldemar Puszkarz_, May 21 2016

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Last modified April 16 17:00 EDT 2024. Contains 371749 sequences. (Running on oeis4.)