A111425 - OEIS

%I #15 Jul 21 2021 07:10:57

%S 0,0,0,1,1,4,24,504,66012,181997601,65720971788709,

%T 65431225571591367370292,23523635785731871586396890786299881280,

%U 8419860898569880503664421048610377961601349941695806840602396

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

%H Alois P. Heinz, <a href="/A111425/b111425.txt">Table of n, a(n) for n = 0..18</a>

%F a(n) = A000073(A000045(n)).

%p a:= n-> (<<0|1|0>, <0|0|1>, <1|1|1>>^((<<0|1>, <1|1>>^n)[1, 2]))[1, 3]:

%p seq(a(n), n=0..14);  # _Alois P. Heinz_, Aug 09 2018

%Y Cf. A000045, A000073, A007570, A111431.

%K easy,nonn

%O 0,6

%A _Jonathan Vos Post_, Nov 13 2005