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A142474 1 followed by A141015. 2
1, 0, 1, 2, 4, 9, 19, 41, 88, 189, 406, 872, 1873, 4023, 8641, 18560, 39865, 85626, 183916, 395033, 848491, 1822473, 3914488, 8407925, 18059374, 38789712, 83316385, 178955183, 384377665, 825604416, 1773314929, 3808901426, 8181135700, 17572253481, 37743426307 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Essentially the same as A078039, A141015, and A141683.

LINKS

Colin Barker, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (1,2,1).

FORMULA

From Colin Barker, Jun 29 2017: (Start)

G.f.: x*(1 - x - x^2) / (1 - x - 2*x^2 - x^3).

a(n) = a(n-1) + 2*a(n-2) + a(n-3) for n>3.

(End)

MATHEMATICA

Table[ ExpandAll[SeriesCoefficient[Series[(1 + t)/(t^3 + t + 1), {t, 0, 30}], n]], {n, 0, 30, 2}]

PROG

(PARI) Vec(x*(1 - x - x^2) / (1 - x - 2*x^2 - x^3) + O(x^50)) \\ Colin Barker, Jun 29 2017

CROSSREFS

Sequence in context: A299106 A141015 A141683 * A078039 A305380 A275862

Adjacent sequences:  A142471 A142472 A142473 * A142475 A142476 A142477

KEYWORD

nonn,less,easy

AUTHOR

Roger L. Bagula, Sep 21 2008

EXTENSIONS

More terms from G. C. Greubel, Jun 26 2017

STATUS

approved

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Last modified March 31 23:42 EDT 2020. Contains 333152 sequences. (Running on oeis4.)