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%I #27 May 26 2022 07:08:22
%S 2,5,3,29,7,13,17,197,41,5741,11,33461,239,269,577,8297,199,179057,59,
%T 45697,5741,982789,1153,29201,33461,146449,337,44560482149,269,
%U 3272609,665857,52734529,15607,1800193921,199,1101341,9369319,4605197,5521,1746860020068409
%N Largest prime factor of the n-th Pell number, A000129(n).
%C First differs from A246556 at n = 17. Since Pell(17) = 1136689 = 137 * 8297, we find that 137 does not divide any earlier Pell number, and hence A246556(17) = 137, but 8297 is also prime, and so a(17) = 8297.
%H Daniel Suteu and Jon E. Schoenfield, <a href="/A264137/b264137.txt">Table of n, a(n) for n = 2..630</a> (terms a(2)..a(240) from Jon E. Schoenfield)
%F a(n) = A006530(A000129(n)).
%t Table[FactorInteger[Fibonacci[n, 2]][[-1, 1]], {n, 25}] (* _Alonso del Arte_, Dec 10 2016 *)
%t FactorInteger[#][[-1,1]]&/@LinearRecurrence[{2,1},{2,5},60] (* _Harvey P. Dale_, Jun 08 2019 *)
%o (PARI) a(n) = vecmax(factor(([2, 1; 1, 0]^n)[2, 1])[,1]); \\ _Daniel Suteu_, May 26 2022
%Y Cf. A000129, A006530, A060385, A246556.
%K nonn
%O 2,1
%A _Jon E. Schoenfield_, Dec 29 2015
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