A332660 Alternate adding and multiplying Fibonacci numbers: a(0) = F(0) + F(1), for n >= 0, a(2n+1) = a(2n) * F(2n+2), a(2n+2) = a(2n+1) + F(2n+3).

1, 1, 3, 9, 14, 112, 125, 2625, 2659, 146245, 146334, 21072096, 21072329, 7944268033, 7944268643, 7840993150641, 7840993152238, 20261126305382992, 20261126305387173, 137066519455944225345

Offset

0,3

Links

Table of n, a(n) for n=0..19.

Example

a(0) = 0 + 1 =  1;
a(1) = 1 * 1 =  1;
a(2) = 1 + 2 =  3;
a(3) = 3 * 3 =  9;
a(4) = 9 + 5 = 14.

Mathematica

a[0] = 1; a[n_] := a[n] = If[OddQ[n], a[n-1] * Fibonacci[n+1], a[n-1] + Fibonacci[n+1]]; Array[a, 20, 0] (* Amiram Eldar, Mar 28 2020 *)

Prog

(Python)
from sympy import fibonacci
f = [fibonacci(n) for n in range(100)]
def a(n):
    out = f[0] + f[1]
    for i in range(1, n):
        if i%2:
            out *= f[i+1]
        else:
            out += f[i+1]
    return out

Crossrefs

Cf. A000045, A047904, A047905, A077138, A222559, A332657, A332659.

Sequence in context: A317038 A317692 A175351 * A343144 A050005 A272026

Adjacent sequences: A332657 A332658 A332659 * A332661 A332662 A332663

Keyword

nonn,less

Author

Adnan Baysal, Feb 18 2020

Status

approved