login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A117691 Expansion of -(x^7+x^6+x^5-2*x^3-3*x^2-3*x-4) / ((x-1)^2*(x+1)^2*(x^2+1)^2). 0
4, 3, 3, 2, 8, 5, 5, 3, 12, 7, 7, 4, 16, 9, 9, 5, 20, 11, 11, 6, 24, 13, 13, 7, 28, 15, 15, 8, 32, 17, 17, 9, 36, 19, 19, 10, 40, 21, 21, 11, 44, 23, 23, 12, 48, 25, 25, 13, 52, 27, 27, 14, 56, 29, 29, 15, 60, 31, 31, 16, 64, 33, 33, 17, 68, 35, 35, 18, 72, 37, 37, 19, 76, 39, 39, 20 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..75.

FORMULA

G.f.: -(x^7+x^6+x^5-2*x^3-3*x^2-3*x-4) / ((x-1)^2*(x+1)^2*(x^2+1)^2). - Colin Barker, Mar 15 2013

a(n) = 2*a(n-4) - a(n-8). - Colin Barker, Mar 15 2013

MATHEMATICA

o = Table[Abs[Coefficient[ExpandAll[(x - (a + I*Sqrt[2*a + 1])/(a + 1))*(x - ( a - I*Sqrt[2*a + 1])/(a + 1))], x]], {a, 1, 100}]; rational = Table[{Numerator[o[[n]]], Denominator[o[[n]]]}, {n, 2, 100}]; Flatten[rational]

t = {4, 3, 3, 2, 8, 5, 5, 3}; Do[AppendTo[t, 2*t[[-4]] - t[[-8]]], {100}]; t (* T. D. Noe, Mar 17 2013 *)

LinearRecurrence[{0, 0, 0, 2, 0, 0, 0, -1}, {4, 3, 3, 2, 8, 5, 5, 3}, 80] (* Harvey P. Dale, Jan 30 2021 *)

CROSSREFS

Sequence in context: A117323 A016502 A305743 * A243564 A358329 A171627

Adjacent sequences: A117688 A117689 A117690 * A117692 A117693 A117694

KEYWORD

nonn,easy

AUTHOR

Roger L. Bagula, Apr 12 2006

EXTENSIONS

New name from Colin Barker, Mar 17 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 3 17:00 EST 2023. Contains 360044 sequences. (Running on oeis4.)