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Search: id:A081169
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| A081169 |
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Triangle in which n-th row gives trajectory of n (including n itself) under the map x -> x/2 if x is even, x -> 3*x-1 if x is odd, stopping when reaching 1, 5 or 17. |
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+0
1
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| 1, 2, 1, 2, 1, 3, 8, 4, 2, 1, 4, 2, 1, 5, 14, 7, 20, 10, 5, 6, 3, 8, 4, 2, 1, 7, 20, 10, 5, 8, 4, 2, 1, 9, 26, 13, 38, 19, 56, 28, 14, 7, 20, 10, 5, 10, 5, 11, 32, 16, 8, 4, 2, 1, 12, 6, 3, 8, 4, 2, 1, 13, 38, 19, 56, 28, 14, 7, 20, 10, 5, 14, 7, 20, 10, 5, 15, 44, 22, 11, 32, 16, 8, 4, 2, 1, 16
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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It is conjectured that the sequence will always end in one of three loops: 1, 2,1,1, ...; 5 14 7 20 10 5...; or 17 50 25 74 37 110 55 164 82 41 122 61 182 91 272 136 68 34 17...
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PROGRAM
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(PARI) xnm3(n) = { print1(1" "2" "1" "); for(x=2, n, x1=x; print1(x1" "); while(x1>1, if(x1%2==0, x1/=2, x1 = 3*p-1); print1(x1" "); if(x1==5 || x1==17, break); ) ) }
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CROSSREFS
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Cf. A080825.
Sequence in context: A133117 A051276 A137752 this_sequence A030359 A035400 A071222
Adjacent sequences: A081166 A081167 A081168 this_sequence A081170 A081171 A081172
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KEYWORD
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easy,nonn,tabf
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Apr 16 2003
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