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A057432
Obtained by reading first the numerator then the denominator of fractions in left-hand half of Stern-Brocot tree (A007305/A007306).
1
1, 1, 1, 2, 1, 3, 2, 3, 1, 4, 2, 5, 3, 5, 3, 4, 1, 5, 2, 7, 3, 8, 3, 7, 4, 7, 5, 8, 5, 7, 4, 5, 1, 6, 2, 9, 3, 11, 3, 10, 4, 11, 5, 13, 5, 12, 4, 9, 5, 9, 7, 12, 8, 13, 7, 11, 7, 10, 8, 11, 7, 9, 5, 6, 1, 7, 2, 11, 3, 14, 3, 13, 4, 15, 5, 18, 5, 17, 4, 13, 5, 14, 7, 19, 8, 21, 7, 18, 7, 17, 8, 19, 7
OFFSET
0,4
MATHEMATICA
Contribution from Peter Luschny, Apr 27 2009: (Start)
sbt[n_]:=Module[{P, L, Y}, P={{1, 0}, {1, 1}}; L={{1, 1}, {0, 1}}; Y={{1, 0}, {0, 1}}; w[b_]:=Fold[ #1.If[ #2==0, L, P]&, Y, b]; u[a_]:={a[[2, 1]]+a[[2, 2]], a[[1, 1]]+a[[1, 2]]}; s[l_]:={l, {Last[l], First[l]}}; Map[s, Map[u, Map[w, Part[Partition[Tuples[{0, 1}, n], 2^(n-1)], 1]]]]]
Flatten[Append[{1, 1}, Table[Map[First, sbt[i]], {i, 1, 5}]]] (End)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Sep 08 2000
EXTENSIONS
More terms from Alford Arnold, Sep 11 2000
More terms from Joshua Zucker, May 11 2006
STATUS
approved