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%I #9 May 11 2019 11:41:42
%S 1,-1,2,1,-2,3,-1,-3,5,-4,-2,8,-9,2,10,-17,11,8,-27,28,-3,-35,55,-31,
%T -32,90,-86,-1,122,-176,85,123,-298,261,38,-421,559,-223,-459,980,
%U -782,-236,1439,-1762,546,1675,-3201,2308,1129,-4876,5509,-1179,-6005,10385,-6688,-4826,16390,-17073,1862,21216
%N Expansion of (1 - x + 2*x^2) / (1 - x^3 + x^4).
%C One of several sequences which appear to "spiral outwards" when plotted against each other (see A110061-A110064).
%H Colin Barker, <a href="/A110062/b110062.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,1,-1).
%F a(n) = a(n-3) - a(n-4) for n>3. - _Colin Barker_, May 11 2019
%p seriestolist(series((1-x+2*x^2)/(1-x^3+x^4), x=0,60)); -or- Floretion Algebra Multiplication Program, FAMP Code: 4ibaseseq[A*B] with A = + .5'i + .5'j + .5'k + .5e and B = - .5'i - .25'j + .25'k - .5i' - .25j' + .25k' - .5'ii' - .25'ij' - .25'ik' - .25'ji' - .25'ki' - .5e
%o (PARI) Vec((1 - x + 2*x^2) / (1 - x^3 + x^4) + O(x^55)) \\ _Colin Barker_, May 11 2019
%Y Cf. A110061, A110063, A110064.
%K easy,sign
%O 0,3
%A _Creighton Dement_, Jul 10 2005
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