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A102423
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Start at 2n+1, iterate the map x -> A102421(x); sequence gives smallest number in resulting cycle, or -1 if the trajectory never cycles.
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2
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1, 1, 1, 1, 1, 1, 1, 17, 17, 17, 1, 1, 1, 17, 1, 1, 1, 1, 1, 1, 1, 17, 1, 1, 1, 1, 1, 1, 1, 1, 17, 1, 1, 1, 17, 1, 1, 17, 17, 1, 1, 1, 1, 1, 1, 1, 1, 17, 17, 1, 1, 1, 1, 17, 17, 1, 1, 1, 1, 1, 17, 17, 1, 1, 1, 1, 1, 17, 17, 1, 1, 1, 1, 1, 1, 1, 17, 1, 1, 1, 1, 1, 1, 1, 17, 17, 17, 1, 1, 1, 1, 1, 1, 1, 1
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OFFSET
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0,8
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COMMENTS
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See A102421 for further comments.
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LINKS
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Table of n, a(n) for n=0..94.
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MATHEMATICA
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nextx[x_Integer] := Block[{a = x}, a = 3a + 1; While[EvenQ@a, a /= 2]; a = 3a - 1; While[EvenQ@a, a /= 2]; a]; f[n_] := NestWhile[nextx, n, MemberQ[{1, 17, 19, 43, 97, 109}, # ] &]; Table[ If[ f[2n + 1] == 1, 1, 17], {n, 0, 94}] (* Robert G. Wilson v, Sep 20 2006 *)
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CROSSREFS
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Sequence in context: A172091 A291370 A291432 * A010856 A291515 A216436
Adjacent sequences: A102420 A102421 A102422 * A102424 A102425 A102426
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane, based on email from Dan Asimov (dasimov(AT)earthlink.net), Sep 15 2006
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EXTENSIONS
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More terms from Robert G. Wilson v, Sep 20 2006
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STATUS
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approved
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