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A373566
Expansion of x - 1/(x - 1/(x + 1)).
1
1, 3, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657, 46368, 75025, 121393, 196418, 317811, 514229, 832040, 1346269, 2178309, 3524578, 5702887, 9227465, 14930352, 24157817, 39088169, 63245986, 102334155
OFFSET
0,2
FORMULA
a(n) = [x^n] (x^3 + x^2 - 2*x - 1) / (x^2 + x - 1).
From Stefano Spezia, Jun 10 2024: (Start)
a(n) = 2^(-n-1)*((1 - sqrt(5))^n*(sqrt(5) - 3) + (1 + sqrt(5))^n*(sqrt(5) + 3))/sqrt(5) for n <> 1.
E.g.f.: x + exp(x/2)*(5*cosh(sqrt(5)*x/2) + 3*sqrt(5)*sinh(sqrt(5)*x/2))/5. (End)
MATHEMATICA
CoefficientList[Series[x - 1/(x - 1/(x + 1)), {x, 0, 38}], x] (* Michael De Vlieger, Jun 10 2024 *)
CROSSREFS
Essentially the same as A071679 and A020695.
Sequence in context: A200737 A200741 A271970 * A213678 A293676 A303714
KEYWORD
nonn,easy
AUTHOR
Peter Luschny, Jun 10 2024
STATUS
approved