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Search: id:A087720
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| A087720 |
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Repeated terms in the Hofstadter batrachian sequence A005185. |
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+0
1
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| 1, 3, 5, 6, 8, 11, 12, 14, 16, 17, 23, 24, 30, 32, 43, 47, 48, 54, 60, 72, 80, 83, 84, 92, 94, 96, 148, 172, 175, 178, 185, 186, 192, 215, 222, 228, 230, 252, 273, 301, 308, 338, 350, 372, 380, 382, 384, 408, 468, 517, 574, 593, 624, 673, 678, 738, 748, 762, 764, 789
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Repeating consecutive elements is a characteristic of chaotic sequences.
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FORMULA
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a[n] =a[n - a[n-1]] + a[n - a[n-2]]
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MATHEMATICA
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digits=30000 Hofstadter[n_Integer?Positive] := Hofstadter[n] = Hofstadter[n - Hofstadter[n-1]] + Hofstadter[n - Hofstadter[n-2]] Hofstadter[1] = Hofstadter[2] = 1 a1=Table[Hofstadter[n], {n, 1, digits}]; b=Table[If[a1[[n]]-a1[[n-1]]==0, a1[[n]], 0], {n, 2, digits}]; c=Delete[Union[b], 1]
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CROSSREFS
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Cf. A005185.
Adjacent sequences: A087717 A087718 A087719 this_sequence A087721 A087722 A087723
Sequence in context: A084810 A014254 A131422 this_sequence A047444 A121501 A062832
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KEYWORD
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nonn
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AUTHOR
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Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Sep 29 2003
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