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A221863 Expansion of (1-3*x+x^2)/(1-9*x+28*x^2-35*x^3+15*x^4-x^5). 1
1, 6, 27, 110, 429, 1637, 6172, 23104, 86090, 319792, 1185305, 4386331, 16212913, 59873834, 220964744, 815057639, 3005282745, 11077802256, 40824723483, 150424044413, 554183037617, 2041477665799, 7519722443381, 27696997721940, 102010147865915, 375697698147882 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

A diagonal of the square array A223968.

LINKS

Table of n, a(n) for n=0..25.

Index entries for linear recurrences with constant coefficients, signature (9,-28,35,-15,1).

FORMULA

a(n) = A223968(n,n+4) = A223968(n,n+5).

G.f.: (1-3*x+x^2)/(1-9*x+28*x^2-35*x^3+15*x^4-x^5).

a(n) = 9*a(n-1) - 28*a(n-2) + 35*a(n-3) - 15*a(n-4) + a(n-5) with a(0) = 1, a(1) = 6, a(2) = 27, a(3) = 110, a(4) = 429.

MATHEMATICA

CoefficientList[Series[(1-3x+x^2)/(1-9x+28x^2-35x^3+15x^4-x^5), {x, 0, 30}], x] (* or *) LinearRecurrence[{9, -28, 35, -15, 1}, {1, 6, 27, 110, 429}, 30] (* Harvey P. Dale, Jan 26 2015 *)

CROSSREFS

Cf. A223968

Sequence in context: A037604 A022634 A094788 * A216263 A003517 A108958

Adjacent sequences:  A221860 A221861 A221862 * A221864 A221865 A221866

KEYWORD

nonn,easy

AUTHOR

Philippe Deléham, Apr 10 2013

STATUS

approved

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Last modified October 16 20:34 EDT 2018. Contains 316275 sequences. (Running on oeis4.)