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A364820
a(n) is the smallest prime factor of the n-th Pell number A000129(n).
2
2, 5, 2, 29, 2, 13, 2, 5, 2, 5741, 2, 33461, 2, 5, 2, 137, 2, 37, 2, 5, 2, 229, 2, 29, 2, 5, 2, 44560482149, 2, 61, 2, 5, 2, 13, 2, 593, 2, 5, 2, 1746860020068409, 2, 11437, 2, 5, 2, 3761, 2, 13, 2, 5, 2, 68480406462161287469, 2, 29, 2, 5, 2
OFFSET
2,1
LINKS
FORMULA
a(n) = A020639(A000129(n)).
MATHEMATICA
FactorInteger[#][[1, 1]] & /@ LinearRecurrence[{2, 1}, {2, 5}, 57] (* Amiram Eldar, Oct 21 2023 *)
CROSSREFS
Cf. A246556 (smallest primitive factor), A264137, A280104, A060383, A020639.
Sequence in context: A298664 A319201 A019295 * A373146 A328264 A170908
KEYWORD
nonn
AUTHOR
Sean A. Irvine, Oct 21 2023
STATUS
approved