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!)
A202012 Expansion of (1-x+x^2)/((1-x)(1-x-x^2-x^3)). 1
1, 1, 3, 6, 11, 21, 39, 72, 133, 245, 451, 830, 1527, 2809, 5167, 9504, 17481, 32153, 59139, 108774, 200067, 367981, 676823, 1244872, 2289677, 4211373, 7745923, 14246974, 26204271, 48197169, 88648415, 163049856 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
Antidiagonal sums of triangle T(n,k) = A104040(n,k)*(-1)^floor(k/2). - Philippe Deléham, Dec 11 2011
LINKS
FORMULA
a(n) = 2*a(n-1) - a(n-4), n>3.
a(n) = A008937(n-1) - A008937(n) + A008937(n+1). - R. J. Mathar, Dec 10 2011
a(n+1)-a(n) = A081172(n+2). - Philippe Deléham, Dec 11 2011
MATHEMATICA
CoefficientList[Series[(1-x+x^2)/((1-x)(1-x-x^2-x^3)), {x, 0, 40}], x] (* or *) LinearRecurrence[{2, 0, 0, -1}, {1, 1, 3, 6}, 40] (* Harvey P. Dale, Apr 21 2014 *)
CROSSREFS
Sequence in context: A018174 A050951 A291408 * A261392 A251655 A132658
KEYWORD
easy,nonn,changed
AUTHOR
Philippe Deléham, Dec 08 2011
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 April 14 20:39 EDT 2024. Contains 371667 sequences. (Running on oeis4.)