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Denominator of the ratio of the preceding two terms.
1

%I #4 Oct 01 2013 17:58:01

%S 1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,

%T 1,1,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,1,1,

%U 2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1,1,1,2,2,1,1

%N Denominator of the ratio of the preceding two terms.

%C The actual repeating sequence is 2,1,1/2,1/2,1,2,2,1,1/2,1/2,1,2...

%F Let a(1) = 1, a(2) = 2 then a(n) = a(n-2)/a(n-1) for n = 3, 4, 5... The sequence only posts the denominator of a(n).

%o (PARI) fibdiv(n) = { a = vector(1000); a[1] = 1; a[2] = 2; for(j=3,n, a[j] = a[j-1]/a[j-2]; print1(denominator(a[j])",") ) }

%K nonn,frac

%O 3,3

%A _Cino Hilliard_, Jun 24 2004