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 A117077 Define binary strings S(0)=0, S(1)=1, S(n) = S(n-2)S(n-1); a(n) = S(n) converted to decimal. 0
 0, 1, 1, 5, 13, 173, 3501, 1420717, 7343549869, 24407739551034797, 264579267653248177273154989, 15107659029337673520218077770654501397966253, 5900314832748922900613950065282124787723453785544193308390237364661677 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS Note that S(n) in general has leading zeros. LINKS FORMULA S(0) = 0, S(1) = 1, so S(2) = 01, a(2) = 1. Use the substitution system 0->1 and 1->01. The values generated from a(0)=0 are 1, 01, 101, 01101, which in base 10 give the sequence. - Jon Perry, Feb 06 2011 EXAMPLE 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). MATHEMATICA 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, Apr 20 2006 *) CROSSREFS Cf. A063896. Sequence in context: A187894 A214591 A159261 * A124924 A209271 A124878 Adjacent sequences:  A117074 A117075 A117076 * A117078 A117079 A117080 KEYWORD base,nonn AUTHOR Jordan Goldstein (jboymicro20X6(AT)aim.com), Apr 18 2006 EXTENSIONS More terms from Robert G. Wilson v, Apr 20 2006 Edited by N. J. A. Sloane, Apr 23 2006 STATUS approved

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Last modified May 14 19:53 EDT 2021. Contains 343903 sequences. (Running on oeis4.)