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

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A117374 Expansion of (1-3x)/(1-x^2+x^3). 2
1, -3, 1, -4, 4, -5, 8, -9, 13, -17, 22, -30, 39, -52, 69, -91, 121, -160, 212, -281, 372, -493, 653, -865, 1146, -1518, 2011, -2664, 3529, -4675, 6193, -8204, 10868, -14397, 19072, -25265, 33469 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Diagonal sums of number triangle A117372.

LINKS

Table of n, a(n) for n=0..36.

Index entries for linear recurrences with constant coefficients, signature (0,1,-1).

FORMULA

a(n)=a(n-2)+a(n-3); a(n)=sum{k=0..floor(n/2), (-1)^n*(C(k,n-2k)+3*C(k, n-2k-1))}.

CROSSREFS

Sequence in context: A260502 A014388 A186693 * A202142 A021322 A277129

Adjacent sequences:  A117371 A117372 A117373 * A117375 A117376 A117377

KEYWORD

easy,sign

AUTHOR

Paul Barry, Mar 10 2006

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 December 6 11:48 EST 2021. Contains 349563 sequences. (Running on oeis4.)