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!)
A077922 Expansion of (1-x)^(-1)/(1+2*x-x^2+x^3). 3
1, -1, 4, -9, 24, -60, 154, -391, 997, -2538, 6465, -16464, 41932, -106792, 271981, -692685, 1764144, -4492953, 11442736, -29142568, 74220826, -189026955, 481417305, -1226082390, 3122609041, -7952717776, 20254126984, -51583580784, 131374006329, -334585720425, 852129027964 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
FORMULA
a(n) = (1 + 2*A077986(n) + A077986(n-2))/3. - R. J. Mathar
MAPLE
A077986 := proc(n) if n < 0 then 0; else coeftayl( 1/(1+2*x-x^2+x^3), x=0, n) ; end if; end proc:
A077922 := proc(n) (1+2*A077986(n)+A077986(n-2))/3 ; end proc:
seq(A077922(n), n=0..20) ; # R. J. Mathar, Mar 24 2011
MATHEMATICA
CoefficientList[Series[1/((1 + 2*x - x^2 + x^3)(1 - x)), {x, 0, 30}], x]
LinearRecurrence[{-1, 3, -2, 1}, {1, -1, 4, -9}, 40] (* Harvey P. Dale, Feb 10 2024 *)
PROG
(PARI) Vec((1-x)^(-1)/(1+2*x-x^2+x^3)+O(x^99)) \\ Charles R Greathouse IV, Sep 26 2012
CROSSREFS
Cf. A010907.
Sequence in context: A304908 A127979 A112262 * A081149 A059507 A128416
KEYWORD
sign,easy
AUTHOR
N. J. A. Sloane, Nov 17 2002
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 March 29 00:26 EDT 2024. Contains 371264 sequences. (Running on oeis4.)