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Search: id:A117077
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| A117077 |
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Define binary strings S(0)=0, S(1)=1, S(n) = S(n-2)S(n-1); a(n) = S(n) converted to decimal. |
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+0
1
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| 0, 1, 1, 5, 13, 173, 3501, 1420717, 7343549869, 24407739551034797, 264579267653248177273154989, 15107659029337673520218077770654501397966253, 5900314832748922900613950065282124787723453785544193308390237364661677
(list; graph; listen)
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OFFSET
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0,4
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COMMENT
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Note that S(n) in general has leading zeros.
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FORMULA
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S(0) = 0, S(1) = 1, so S(2) = 01, a(2) = 1.
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EXAMPLE
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S(3) = 01 (base 2) = 1 (base 10) so a(3) = 1.
S(4) = 101 (base 2) = 5 (base 10) so a(4) = 5.
S(5) = 01.101 = 01101 (base 2) = 13 (base 10) so a(5) = 13.
S(6) = 101.01101 = 10101101 (base 2) = 173 (base 10) so a(6) = 173.
S(7) = 01101.10101101 = 0110110101101 (base 2) = 3501 (base 10).
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MATHEMATICA
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a[1] = 0; a[2] = 1; a[n_] := a[n] = If[ OddQ@n, FromDigits[ Join[ IntegerDigits[ a[n - 2], 2], IntegerDigits[ a[n - 1], 2]], 2], FromDigits[ Join[ IntegerDigits[ a[n - 2], 2], {0}, IntegerDigits[ a[n - 1], 2]], 2]]; Array[a, 13] (* Robert G. Wilson v *)
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CROSSREFS
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Cf. A063896.
Sequence in context: A005764 A099974 A159261 this_sequence A124924 A124878 A085554
Adjacent sequences: A117074 A117075 A117076 this_sequence A117078 A117079 A117080
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KEYWORD
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base,nonn,word
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AUTHOR
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Jordan Goldstein (jboymicro20X6(AT)aim.com), Apr 18 2006
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(at)rgwv.com), Apr 20 2006
Edited by N. J. A. Sloane (njas(AT)research.att.com), Apr 23 2006
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