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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A122509 Expansion of x/(1 - 2*x^2 - 21*x^3). 1
 0, 1, 0, 2, 21, 4, 84, 449, 252, 2662, 9933, 10616, 75768, 229825, 374472, 2050778, 5575269, 11965468, 54216876, 141011585, 359708580, 1420577566, 3680660445, 10395035312, 37193449776, 98083939969, 292682641104, 977230325234 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS G. C. Greubel, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (0,2,21). FORMULA G.f.: x/(1 - 2*x^2 - 21*x^3). MATHEMATICA CoefficientList[Series[x/(1 -2*x^2 -21*x^3), {x, 0, 30}], x] PROG (Magma) I:=[0, 1, 0]; [n le 3 select I[n] else 2*Self(n-2) +21*Self(n-3): n in [1..31]]; // G. C. Greubel, Jul 11 2021 (Sage) def A122509_list(prec): P. = PowerSeriesRing(ZZ, prec) return P( x/(1 -2*x^2 -21*x^3) ).list() A122509_list(30) # G. C. Greubel, Jul 11 2021 CROSSREFS Sequence in context: A162536 A100980 A360980 * A024230 A358520 A105666 Adjacent sequences: A122506 A122507 A122508 * A122510 A122511 A122512 KEYWORD nonn,easy AUTHOR Roger L. Bagula, Sep 15 2006 EXTENSIONS Edited by G. C. Greubel, Jul 11 2021 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.

Last modified June 25 13:13 EDT 2024. Contains 373705 sequences. (Running on oeis4.)