A221018 Number n such that Fibonacci(n) is divisible by n, n + 1 and n - 1.

108, 2688, 3528, 4968, 6480, 15288, 18048, 20808, 21000, 25308, 35448, 47520, 62928, 68208, 81648, 82008, 97608, 103968, 108288, 116928, 137088, 139968, 151848, 162288, 196560, 197568, 200928, 235008, 238728, 253368, 278208, 363888, 379008, 400248, 444528, 449568, 457608

Offset: 1

Author

Alex Ratushnyak, May 03 2013

Keywords

• nonn

Comments

Numbers n such that Fibonacci(n) mod n = Fibonacci(n) mod (n-1) = Fibonacci(n) mod (n+1) = 0.

Subsequence of A023172.

Links

• Chai Wah Wu, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A000045, A023172, A225219.

Programs

Python

prpr, prev = 0, 1
for n in range(2, 100000):
    prpr, prev = prev, prpr+prev
    if n%2: continue
    if (prev % n, prev % (n-1), prev % (n+1)) == (0, 0, 0):
        print(n, end=", ")