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A133421
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Image of n under one application of the "7x+1" map.
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4
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8, 1, 1, 2, 1, 3, 50, 4, 3, 5, 78, 6, 92, 7, 5, 8, 120, 9, 134, 10, 7, 11, 162, 12, 5, 13, 9, 14, 204, 15, 218, 16, 11, 17, 7, 18, 260, 19, 13, 20, 288, 21, 302, 22, 15, 23, 330, 24, 344, 25, 17, 26, 372, 27, 11, 28, 19, 29, 414, 30, 428, 31, 21, 32, 13, 33, 470, 34, 23, 35, 498
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The 7x+1 map sends x to x/2 if x is even, x/3 if x is divisible by 3, x/5 if x is divisible by 5, otherwise 7x+1.
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LINKS
| Tomas Oliveira e Silva, The px+1 problem
Index entries for sequences related to 3x+1 (or Collatz) problem
Harvey P. Dale, Table of n, a(n) for n = 1..10000
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MATHEMATICA
| Table[Nest[Which[EvenQ[#], #/2, Divisible[#, 3], #/3, Divisible[#, 5], #/5, True, 7#+1]&, n, 1], {n, 75}] (* From Harvey P. Dale, Nov 05 2011 *)
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CROSSREFS
| Cf. A133422, A133419, ...
Sequence in context: A066341 A181064 A010153 * A128881 A154015 A197492
Adjacent sequences: A133418 A133419 A133420 * A133422 A133423 A133424
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Nov 27 2007
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EXTENSIONS
| More terms from Sean A. Irvine (sairvin(AT)xtra.co.nz), Mar 29 2010
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