A366583 - OEIS

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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

(list; graph; refs; listen; history; text; internal format)

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