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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A105811 Expansion of (1+x-x^2)/(1+x)^2. 6
 1, -1, 0, 1, -2, 3, -4, 5, -6, 7, -8, 9, -10, 11, -12, 13, -14, 15, -16, 17, -18, 19, -20, 21, -22, 23, -24, 25, -26, 27, -28, 29, -30, 31, -32, 33, -34, 35, -36, 37, -38, 39, -40, 41, -42, 43, -44, 45, -46, 47, -48, 49, -50, 51, -52, 53, -54, 55, -56, 57, -58, 59, -60, 61, -62, 63, -64, 65 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS First column of number triangle A105810. LINKS Index entries for linear recurrences with constant coefficients, signature (-2,-1). FORMULA a(n) = -0^n-(-1)^n*(n-2). MATHEMATICA CoefficientList[Series[(1+x-x^2)/(1+x)^2, {x, 0, 70}], x] (* or *) LinearRecurrence[ {-2, -1}, {1, -1, 0}, 70] (* Harvey P. Dale, Jun 16 2016 *) PROG (PARI) a(n)=-0^n-(-1)^n*(n-2) \\ Charles R Greathouse IV, Sep 02 2015 CROSSREFS Sequence in context: A001478 A001489 A038608 * A209662 A272813 A258070 Adjacent sequences:  A105808 A105809 A105810 * A105812 A105813 A105814 KEYWORD easy,sign AUTHOR Paul Barry, May 04 2005 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.

Last modified August 8 14:04 EDT 2020. Contains 336298 sequences. (Running on oeis4.)