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A291388 a(n) = (1/8)*A291387(n). 2
1, 7, 44, 262, 1504, 8416, 46208, 250016, 1337088, 7083264, 37229568, 194383360, 1009172480, 5213634560, 26819756032, 137445318656, 702021435392, 3574958587904, 18156130926592, 91985567678464, 465004476235776, 2345955741401088, 11813573860786176 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Clark Kimberling, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (8,-8,-32,-16)

FORMULA

G.f.: -(((1 + x) (-1 + 2 x + 2 x^2))/(-1 + 4 x + 4 x^2)^2).

a(n) = 8*a(n-1) - 8*a(n-2) - 32*a(n-3) - 16*a(n-4) for n >= 5.

MATHEMATICA

z = 60; s = x + x^2; p = (1 - 4 s)^2;

Drop[CoefficientList[Series[s, {x, 0, z}], x], 1]  (* A019590 *)

u = Drop[CoefficientList[Series[1/p, {x, 0, z}], x], 1]  (* A291387 *)

u / 8  (* A291388 *)

PROG

(GAP)

a:=8*[1, 7, 44, 262];; for n in [5..10^2] do a[n]:=8*a[n-1]+-8*a[n-2]-32*a[n-3]-16*a[n-4]; od;

A291388:=(1/8)*a;  # Muniru A Asiru, Sep 07 2017

CROSSREFS

Cf. A019590, A291382, A291388.

Sequence in context: A323923 A026116 A216237 * A037531 A178719 A094113

Adjacent sequences:  A291385 A291386 A291387 * A291389 A291390 A291391

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Sep 04 2017

STATUS

approved

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Last modified October 20 22:22 EDT 2021. Contains 348119 sequences. (Running on oeis4.)