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A083557 a(n) is the greatest prime factor of 3*a(n-1)+2. 1
3, 11, 7, 23, 71, 43, 131, 79, 239, 719, 127, 383, 1151, 691, 83, 251, 151, 13, 41, 5, 17, 53, 23, 71, 43, 131, 79, 239, 719, 127, 383, 1151, 691, 83, 251, 151, 13, 41, 5, 17, 53, 23, 71, 43, 131, 79, 239, 719, 127, 383, 1151, 691, 83, 251, 151, 13, 41, 5, 17, 53, 23 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

Conjecture: if a(1)=m then the sequence becomes cyclic, for any m.

MATHEMATICA

f[n_] := Flatten[Table[ #[[1]], {1}] & /@ FactorInteger[ 3n + 2 ]][[ -1]]; NestWhileList[f, 3, UnsameQ, All]

CROSSREFS

Cf. A031439, A031440, A031442, A082021, A082132, A084923.

Sequence in context: A196171 A164808 A153285 * A119324 A006495 A112286

Adjacent sequences:  A083554 A083555 A083556 * A083558 A083559 A083560

KEYWORD

nonn

AUTHOR

Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp), Jun 05 2003

EXTENSIONS

Conjecture verified by Jud McCranie up to 25000000. Jun 11, 2003

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Last modified February 13 08:12 EST 2012. Contains 205451 sequences.