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A355299

Largest prime factor of n-th term in Look and Say sequence A005150, with a(1)=1.

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