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A291788
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Numbers n whose trajectory under the map k -> (psi(k)+phi(k))/2 (A291784) grows without limit.
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4
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45, 48, 50, 55, 56, 60, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 102, 104, 105, 108, 111, 112, 115, 116, 117, 118, 119, 120, 122, 123, 124, 126, 133, 134, 135, 136, 140, 141, 142, 143, 144, 145, 146, 147, 152
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OFFSET
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1,1
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COMMENTS
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See A291787 (where A291787(m) = 2*A291787(m-7) for m >= 35) for the trajectory of 45.
There is a similar proof that all the terms from 48 though 152 have a trajectory that merges with the trajectory of 45, and so doubles every 7 steps after a certain point. For example, the trajectory of 152 reaches 2^106*33 at step 390, is 2^107*33 at step 397, and thereafter doubles every 7 steps.- N. J. A. Sloane, Sep 24 2017
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LINKS
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Table of n, a(n) for n=1..59.
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CROSSREFS
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Cf. A291784, A291785, A291786, A291787.
Sequence in context: A031064 A183983 A116334 * A291787 A257410 A306103
Adjacent sequences: A291785 A291786 A291787 * A291789 A291790 A291791
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KEYWORD
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nonn,more
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AUTHOR
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N. J. A. Sloane, Sep 03 2017, based on data supplied by Hans Havermann.
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EXTENSIONS
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Terms 104 to 152 added by N. J. A. Sloane, Sep 24 2017
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STATUS
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approved
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