A058051 - OEIS

%I #16 Feb 09 2018 19:42:40

%S 0,1,1,1,1,5,10946,2211236406303914545699412969744873993387956988653

%N a(n) = F(F(F(n))), where F is a Fibonacci number (A000045).

%C a(8) = 1695216512..7257812353 has 2288 decimal digits and a(9) = 3525796792..4659808333 has 1191833 decimal digits. - _Alois P. Heinz_, Nov 11 2015

%p F:= n-> (<<0|1>, <1|1>>^n)[1, 2]:

%p a:= n-> F(F(F(n))):

%p seq(a(n), n=0..7);  # _Alois P. Heinz_, Nov 11 2015

%t F[0] = 0; F[1] = 1; F[n_] := F[n] = F[n - 1] + F[n - 2]; Table[ F[ F[ F[n] ] ], {n, 0, 10} ]

%t Table[Nest[Fibonacci,n,3],{n,0,8}] (* _Harvey P. Dale_, Feb 09 2018 *)

%Y Cf. A000045, A007570, A262361.

%K easy,nonn

%O 0,6

%A _Robert G. Wilson v_, Nov 18 2000

%E Offset corrected by _Alois P. Heinz_, Nov 11 2015