login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A158020 Triangle of coefficients in expansion of (-1-x)^floor(n/2)(1-x)^ceiling(n/2). 2
1, 1, -1, -1, 0, 1, -1, 1, 1, -1, 1, 0, -2, 0, 1, 1, -1, -2, 2, 1, -1, -1, 0, 3, 0, -3, 0, 1, -1, 1, 3, -3, -3, 3, 1, -1, 1, 0, -4, 0, 6, 0, -4, 0, 1, 1, -1, -4, 4, 6, -6, -4, 4, 1, -1, -1, 0, 5, 0, -10, 0, 10, 0, -5, 0, 1, -1, 1, 5, -5, -10, 10, 10, -10, -5, 5, 1, -1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,13

COMMENTS

Triangle T(n,k), 0 <= k <= n, read by rows given by [1,-2,1,0,0,0,0,0,0,...] DELTA [-1,0,1,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938.

LINKS

Table of n, a(n) for n=0..77.

FORMULA

T(n,k) = T(n-2,k-2) - T(n-2,k), T(0,0)=T(1,0)=1, T(1,1)=-1.

G.f.: (1+(1-y)*x)/(1+(1-y^2)*x^2). - Philippe Deléham, Dec 02 2011

EXAMPLE

Triangle begins:

   1;

   1, -1;

  -1,  0,  1;

  -1,  1,  1, -1;

   1,  0, -2,  0,  1;  ...

MATHEMATICA

Flatten[Table[CoefficientList[(-1 - x)^Floor[n/2] (1 - x)^Ceiling[n/2], x], {n, 0, 11}]] (* T. D. Noe, Dec 01 2011 *)

CROSSREFS

Cf. A051160.

Sequence in context: A268479 A035196 A287475 * A051160 A051159 A331545

Adjacent sequences:  A158017 A158018 A158019 * A158021 A158022 A158023

KEYWORD

sign,tabl

AUTHOR

Philippe Deléham, Mar 11 2009

EXTENSIONS

Corrected by Philippe Deléham, Dec 02 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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 15 04:53 EDT 2021. Contains 342975 sequences. (Running on oeis4.)