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!)
A130507 First differences of A130845. 1
0, 0, 1, 0, 0, 0, 2, -1, 0, 0, 3, -2, 0, 0, 4, -3, 0, 0, 5, -4, 0, 0, 6, -5, 0, 0, 7, -6, 0, 0, 8, -7, 0, 0, 9, -8, 0, 0, 10, -9, 0, 0, 11, -10, 0, 0, 12, -11, 0, 0, 13, -12, 0, 0, 14, -13, 0, 0, 15, -14, 0, 0, 16, -15, 0, 0, 17, -16, 0, 0, 18, -17, 0, 0, 19, -18, 0, 0, 20, -19, 0, 0, 21, -20, 0, 0, 22, -21, 0, 0, 23, -22, 0, 0, 24, -23, 0, 0, 25, -24, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,7

LINKS

Colin Barker, Table of n, a(n) for n = 0..1000

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

FORMULA

a(n) = (1/16)*(cos(n*Pi/2)+sin(n*Pi/2)-1)*((2n-1)*cos(n*Pi/2)-5*cos(n*Pi)+(2n-1)*sin(n*Pi/2))*(-1)^floor((n-1)/2). - Wesley Ivan Hurt, Sep 24 2017

From Colin Barker, Sep 25 2017: (Start)

G.f.: x^2*(1 + x + x^2 + x^3 + x^4) / ((1 - x)*(1 + x)^2*(1 + x^2)^2).

a(n) = -a(n-1) - a(n-2) - a(n-3) + a(n-4) + a(n-5) + a(n-6) + a(n-7) for n>6.

(End)

PROG

(PARI) concat(vector(2), Vec(x^2*(1 + x + x^2 + x^3 + x^4) / ((1 - x)*(1 + x)^2*(1 + x^2)^2) + O(x^100))) \\ Colin Barker, Sep 25 2017

CROSSREFS

Cf. A130845.

Sequence in context: A109264 A322393 A294265 * A281449 A280605 A218253

Adjacent sequences:  A130504 A130505 A130506 * A130508 A130509 A130510

KEYWORD

sign,easy

AUTHOR

Paul Curtz, Aug 16 2007

EXTENSIONS

One term corrected by Colin Barker, Sep 25 2017

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 September 16 07:19 EDT 2021. Contains 347469 sequences. (Running on oeis4.)