A377184 Numbers k such that L(k)+1 is prime, where L(k) is the k-th Lucas number.

0, 1, 3, 6, 18

Offset: 1

Author

Harsh Aggarwal, Oct 18 2024

Keywords

• nonn
• more

Comments

Positive terms must be a power of 3 or twice a power of 3. All other terms have trivial factors. No other terms under 10^7 (a(6) > 10^7).

Examples

			18 is a term because L(18)+1 = 5779 which is prime. Also 18 = 2*3^2.
		

Crossrefs

Indices of primes in A001612.

Cf. A000032, A000204, A001606.