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Coefficients of 1/(Sum_{k>=0} [(k+1)*r](-x)^k), where r = 4^(1/3) and [ ] = floor.
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%I #4 Jul 10 2017 22:50:43

%S 1,3,5,9,18,36,71,138,268,522,1017,1981,3859,7517,14642,28521,55557,

%T 108223,210814,410654,799931,1558224,3035341,5912689,11517614,

%U 22435718,43703622,85132404,165833537,323035186,629255898,1225758065,2387713549,4651142959

%N Coefficients of 1/(Sum_{k>=0} [(k+1)*r](-x)^k), where r = 4^(1/3) and [ ] = floor.

%C Conjecture: the sequence is strictly increasing.

%F G.f.: 1/(Sum_{k>=0} [(k+1)*r)](-x)^k), where r = 4^(1/3) and [ ] = floor.

%t r = Sqrt[5/2];

%t u = 1000; (* # initial terms from given series *)

%t v = 100; (* # coefficients in reciprocal series *)

%t CoefficientList[Series[1/Sum[Floor[r*(k + 1)] (-x)^k, {k, 0, u}], {x, 0, v}], x]

%Y Cf. A078140 (includes guide to related sequences).

%K nonn,easy

%O 0,2

%A _Clark Kimberling_, Jul 10 2017