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A355299
Largest prime factor of n-th term in Look and Say sequence A005150, with a(1)=1.
0
1, 11, 7, 173, 10111, 312211, 13112221, 2909, 5578070441, 489923144699, 76572179303098543109, 244020609982169, 46889682313579293049990557739475858123, 213414262009265690085197238570402233414850657035591, 323082514382425741194809828536919444925509282219
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OFFSET
1,2
COMMENTS
The terms in A005150 that are known to be primes are a(2) = 11, a(6) = 312211 and a(7) = 13112221 (A100108).
The corresponding smallest prime factor is A334132(n).
LINKS
Table of n, a(n) for n=1..15.
Wikipedia, Look-and-say sequence.
FORMULA
a(n) = A006530(A005150(n)).
EXAMPLE
A005150(7) = 13112221 is prime and a(7) = 13112221.
A005150(8) = 1113213211 = 11 * 19 * 1831 * 2909, hence a(8) = 2909.
CROSSREFS
Cf. A005150, A006530, A079562, A100108, A334132.
Sequence in context: A060954 A350214 A038321 * A298438 A262866 A002749
Adjacent sequences: A355296 A355297 A355298 * A355300 A355301 A355302
KEYWORD
nonn,base
AUTHOR
Bernard Schott, Jun 27 2022
STATUS
approved

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Last modified October 21 05:36 EDT 2024. Contains 376969 sequences.
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