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Search: id:A056959
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| A056959 |
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In repeated iterations of function m->m/2 if m even, m->3m+1 if m odd, a(n) is maximum value achieved if starting from n. |
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+0
4
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| 4, 4, 16, 4, 16, 16, 52, 8, 52, 16, 52, 16, 40, 52, 160, 16, 52, 52, 88, 20, 64, 52, 160, 24, 88, 40, 9232, 52, 88, 160, 9232, 32, 100, 52, 160, 52, 112, 88, 304, 40, 9232, 64, 196, 52, 136, 160, 9232, 48, 148, 88, 232, 52, 160, 9232, 9232, 56, 196, 88, 304, 160, 184
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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If a(n) exists (which is the essence of the 3x+1 "problem") then a(n) must be a multiple of 4, since if a(n) was odd then the next iteration 3*a(n)+1 would be greater than a(n), while if a(n) was twice an odd number then the next-but-one iteration (3/2)*a(n)+1 would be greater.
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LINKS
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Index entries for sequences related to 3x+1 (or Collatz) problem
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EXAMPLE
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a(9)=16 since iteration starts: 6, 3, 10, 5, 16, 8, 4, 2, 1, 4, 2, 1, ... and 16 is highest value
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CROSSREFS
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Cf. A006370, A056957, A056958.
Essentially the same as A025586.
Sequence in context: A068592 A135944 A076821 this_sequence A102376 A091278 A127473
Adjacent sequences: A056956 A056957 A056958 this_sequence A056960 A056961 A056962
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KEYWORD
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nonn
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AUTHOR
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Henry Bottomley (se16(AT)btinternet.com), Jul 18 2000
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