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A121171 Largest prime divisor of Lucas(5*n), where Lucas(k) = A000032(k). 5
11, 41, 31, 2161, 151, 2521, 911, 3041, 541, 570601, 39161, 20641, 24571, 12317523121, 18451, 23725145626561, 12760031, 10783342081, 87382901, 5738108801, 767131, 59996854928656801, 686551, 23735900452321, 28143378001, 42426476041450801, 119611 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Final digit of a(n) is 1. Mod[a(n),10] = 1. Final digit of many prime divisors of Lucas(5*n) is 1.
LINKS
FORMULA
a(n) = A006530(A000032(5*n)) = A079451(5*n). - Daniel Suteu, May 26 2022
MATHEMATICA
Table[Max[Flatten[FactorInteger[Fibonacci[5n-1]+Fibonacci[5n+1]]]], {n, 1, 40}]
PROG
(PARI)
lucas(n) = fibonacci(n+1)+fibonacci(n-1); \\ A000032
a(n) = vecmax(factor(lucas(5*n))[, 1]); \\ Daniel Suteu, May 26 2022
CROSSREFS
Sequence in context: A065144 A089348 A088622 * A239790 A065079 A065049
KEYWORD
nonn
AUTHOR
Alexander Adamchuk, Aug 14 2006
STATUS
approved

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Last modified April 19 21:09 EDT 2024. Contains 371798 sequences. (Running on oeis4.)