This site is supported by donations to The OEIS Foundation.

 Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS". Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A077966 Expansion of 1/(1+2*x^2). 6
 1, 0, -2, 0, 4, 0, -8, 0, 16, 0, -32, 0, 64, 0, -128, 0, 256, 0, -512, 0, 1024, 0, -2048, 0, 4096, 0, -8192, 0, 16384, 0, -32768, 0, 65536, 0, -131072, 0, 262144, 0, -524288, 0, 1048576, 0, -2097152, 0, 4194304, 0, -8388608, 0, 16777216, 0, -33554432, 0, 67108864, 0, -134217728, 0, 268435456 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Normally sequences like this are not included, since with the alternating 0's deleted it is already in the database. Inverse binomial transform of A087455. - Philippe Deléham, Dec 02 2008 Pisano period lengths: 1, 1, 2, 1, 8, 2, 12, 1, 6, 8, 10, 2, 24, 12, 8, 1, 16, 6, 18, 8,... - R. J. Mathar, Aug 10 2012 LINKS Index entries for linear recurrences with constant coefficients, signature (0,-2) FORMULA a(n) = (1+(-1)^n)*(-2)^(n/2)/2. - R. J. Mathar, Apr 23 2009 a(n) = ((n+1) mod 2 )*(-2)^floor((n+1)/2). - Wesley Ivan Hurt, Apr 06 2014 MAPLE A077966:=n->(1+(-1)^n)*(-2)^(n/2)/2; seq(A077966(n), n=0..50); # Wesley Ivan Hurt, Apr 02 2014 MATHEMATICA CoefficientList[Series[1/(1 + 2*x^2), {x, 0, 200}], x] (* Vladimir Joseph Stephan Orlovsky, Jun 10 2011 *) PROG (Sage) [lucas_number1(n, 0, 2) for n in xrange(1, 58)] # Zerinvary Lajos, Jul 16 2008 (PARI) Vec(1/(1+2*x^2)+O(x^99)) \\ Charles R Greathouse IV, Sep 24 2012 (PARI) for(n=0, 51, print1(imag(quadgen(-8)^(n+1)), ", ")) \\ Arkadiusz Wesolowski, Dec 26 2012 CROSSREFS Cf. A000079, A077957. Sequence in context: A194795 A131575 A077957 * A275670 A021102 A021053 Adjacent sequences:  A077963 A077964 A077965 * A077967 A077968 A077969 KEYWORD sign,easy AUTHOR N. J. A. Sloane, Nov 17 2002 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified November 23 13:09 EST 2017. Contains 295127 sequences.