A377183 Positive numbers k such that L(k)-1 is prime, where L(k) is the k-th Lucas number.

2, 3, 6, 24, 48, 96

Offset: 1

Author

Harsh Aggarwal, Oct 18 2024

Keywords

• nonn
• more

Comments

Terms must be 3-smooth. All other terms have trivial factors. No other terms under 10^7 (a(7) > 10^7).

Examples

			24 is a term because L(24)-1 = 103681 which is prime. Also 24 = 2^2*3^1.
		

Crossrefs

Indices of primes in A001610.

Cf. A000032, A000204, A001606.