0,2

Fixed point of the morphism 1->12, 2->1, starting from a(1) = 2.

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T. D. Noe, Table of n, a(n) for n=0..10945 (20 iterations)

Define strings S(0)=2, S(1)=1, S(n)=S(n-1)S(n-2); iterate. Sequence is S(infinity).

a(n-1)=n-floor(phi*floor(n/phi)) - Benoit Cloitre (benoit7848c(AT)orange.fr), Jul 28 2005

Nest[ Flatten[ # /. {1 -> {1, 2}, 2 -> {1}}] &, {1}, 10] (from Robert G. Wilson v Mar 04 2005)

A003849 is the standard form of this sequence. This is the 2, 1 version. See also A014675, A005614, A001468.

Sequence in context: A131774 A078316 A055443 this_sequence A095771 A007421 A103921

Adjacent sequences: A003839 A003840 A003841 this_sequence A003843 A003844 A003845

nonn,nice,easy

N. J. A. Sloane (njas(AT)research.att.com).