A361510 a(n) = smallest k >= 0 such that Fibonacci(k) + Fibonacci(n) is a prime, or -1 if no such k exists.

3, 1, 1, 0, 0, 0, 4, 0, 3, 4, 9, 0, 5, 0, 3, 4, 9, 0, 16, 24, 18, 4, 3, 0, 7, 12

Offset: 0

Author

Jack Braxton, Mar 26 2023

Keywords

• nonn
• more
• less

Comments

a(26) is currently unknown.

Crossrefs

Cf. A000045, A361509, A361902.

Programs

Maple

See A361509.

Mathematica

a[n_] := Module[{fn = Fibonacci[n], k = 0}, While[! PrimeQ[fn + Fibonacci[k]], k++]; k]; Array[a, 26, 0] (* Amiram Eldar, Mar 30 2023 *)

PARI

a(n) = my(k=0, fn=fibonacci(n)); while (!isprime(fn+fibonacci(k)), k++); k; \\ Michel Marcus, Mar 30 2023

Formula

a(n) = A361902(A000045(n)). - Pontus von Brömssen, Mar 30 2023

Extensions

Edited by N. J. A. Sloane, Mar 30 2023