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

1,1

Comments

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

Links

Table of n, a(n) for n=1..6.

Example

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.

Sequence in context: A295967 A027163 A160683 * A099000 A032540 A063728

Adjacent sequences: A377180 A377181 A377182 * A377184 A377185 A377186

Keyword

nonn,more

Author

Harsh Aggarwal, Oct 18 2024

Status

approved