A366583 a(2) = a(3) = 1; for n >3, a(n) = smallest prime factor of n-th Tribonacci number.

1, 1, 2, 2, 7, 13, 2, 2, 3, 149, 2, 2, 3, 5, 2, 2, 103, 13, 2, 2, 5, 3, 2, 2, 3, 3, 2, 2, 23, 5, 2, 2, 3, 103, 2, 2, 7, 3, 2, 2, 167, 11, 2, 2, 5, 3, 2, 2, 199, 5, 2, 2, 7, 163, 2, 2, 29531, 5, 2, 2, 3, 5, 2, 2, 3, 199, 2, 2, 7, 19, 2, 2, 1259, 3, 2, 2, 3, 3

Offset

2,3

Links

Amiram Eldar, Table of n, a(n) for n = 2..365

Formula

a(n) = A020639(A000073(n)).

Example

For n=24: A000073(24) = 2*2*2*51343, so a(24)=2.

Mathematica

FactorInteger[#][[1, 1]] & /@ LinearRecurrence[{1, 1, 1}, {1, 1, 2}, 78] (* Amiram Eldar, Oct 23 2023 *)

Crossrefs

Cf. A000073, A231575, A101757.

Sequence in context: A047756 A047767 A303588 * A366584 A380740 A019144

Adjacent sequences: A366580 A366581 A366582 * A366584 A366585 A366586

Keyword

nonn

Author

Tyler Busby, Oct 13 2023

Status

approved