login
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).
2
1, 1, 3, 9, 14, 112, 125, 2625, 2659, 146245, 146334, 21072096, 21072329, 7944268033, 7944268643, 7840993150641, 7840993152238, 20261126305382992, 20261126305387173, 137066519455944225345
OFFSET
0,3
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
KEYWORD
nonn,less
AUTHOR
Adnan Baysal, Feb 18 2020
STATUS
approved