login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A084613 a(n) = sum of absolute values of coefficients of (1 + x - 2x^2)^n. 5
1, 4, 14, 44, 124, 394, 1418, 4706, 14322, 40712, 135878, 468934, 1513650, 4502864, 13421408, 45258442, 152708520, 483810550, 1413811358, 4483843328, 15051967962, 49724234652, 154802614364, 461020649750, 1486736569982 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

MATHEMATICA

Table[Total[Abs[CoefficientList[Expand[(1+x-2x^2)^n], x]]], {n, 0, 30}]  (* Harvey P. Dale, Apr 21 2011 *)

PROG

(PARI) for(n=0, 40, S=0; for(k=0, 2*n, t=polcoeff((1+x-2*x^2)^n, k, x); S=S+abs(t)); print1(S", "))

CROSSREFS

Cf. A002426, A084600 to A084612, A084614, A084615.

Sequence in context: A292718 A212688 A261451 * A099063 A057223 A007466

Adjacent sequences:  A084610 A084611 A084612 * A084614 A084615 A084616

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jun 01 2003

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 24 02:32 EDT 2019. Contains 326260 sequences. (Running on oeis4.)