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%I #17 Nov 19 2020 15:17:58
%S 1,-1,-1,1,2,-1,-4,1,7,0,-12,-3,20,10,-32,-25,49,55,-71,-112,95,216,
%T -111,-399,94,710,11,-1220,-316,2024,1037,-3233,-2573,4941,5634,-7137,
%U -11440,9505,22015,-11008,-40592,9073,72112,1934,-123712,-33453,204897,107499,-326675,-264664,498119,577060
%N G.f.: 1/(1 + x + 2*x^2 + 2*x^3 + x^4).
%H Michael D. Hirschhorn, <a href="http://www.fq.math.ca/Papers1/43-4/paper43-4-5.pdf">Non-trivial intertwined second-order recurrence relations</a>, Fibonacci Quart. 43 (2005), no. 4, 316-325. See J_n.
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (-1,-2,-2,-1).
%F a(n) = - a(n-1) - 2*a(n-2) - 2*a(n-3) - a(n-4), n > 3. - _Iain Fox_, Dec 25 2017
%t CoefficientList[Series[1/(1+x+2x^2+2x^3+x^4),{x,0,60}],x] (* or *) LinearRecurrence[ {-1,-2,-2,-1},{1,-1,-1,1},60] (* _Harvey P. Dale_, Nov 19 2020 *)
%o (PARI) first(n) = Vec(1/(1 + x + 2*x^2 + 2*x^3 + x^4) + O(x^n)) \\ _Iain Fox_, Dec 25 2017
%K sign,easy
%O 0,5
%A _N. J. A. Sloane_, Nov 09 2011
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