A130589 a(n) = F(F(n)-1), where F(n) = A000045(n) (the Fibonacci numbers).

1, 0, 0, 1, 1, 3, 13, 144, 6765, 3524578, 86267571272, 1100087778366101931, 343358302784187294870275058337, 1366619256256991435939546543402365995473880912459, 1697726516284295515651670644354144400761613511040643009353262085480136081475307

Offset: 0

Author

Philippe Lallouet (philip.lallouet(AT)wanadoo.fr), Jun 16 2007

Keywords

• easy
• nonn

Examples

			a(1)=F(F(1)-1)=F(0)=0;
a(2)=F(F(2)-1)=F(0)=0;
a(3)=F(F(3)-1)=F(1)=1;
a(4)=F(F(4)-1)=F(2)=1;
a(5)=F(F(5)-1)=F(4)=3;
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..19

Crossrefs

Cf. A000045.

Cf. A007570.

Programs

Maple

with(combinat): a:= proc(n) fibonacci(fibonacci(n)-1) end proc: seq(a(n), n = 0 .. 14);
# second Maple program:
F:= n-> (<<0|1>, <1|1>>^n)[1, 2]:
a:= n-> F(F(n)-1):
seq(a(n), n=0..14);  # Alois P. Heinz, Nov 07 2018

Mathematica

Fibonacci[Fibonacci[Range[15]]-1] (* Harvey P. Dale, Feb 18 2018 *)

Extensions

Edited by Emeric Deutsch, Jul 10 2007

a(0)=1 prepended by Alois P. Heinz, Nov 07 2018