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 A056920 Denominators of continued fraction for left factorial. 3
 1, 1, 0, -1, -1, 1, 4, 1, -15, -19, 56, 151, -185, -1091, 204, 7841, 6209, -56519, -112400, 396271, 1520271, -2442439, -19165420, 7701409, 237686449, 145269541, -2944654296, -4833158329, 36392001815, 104056218421, -441823808804, -2002667085119, 5066513855745, 37109187217649 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,7 LINKS G. C. Greubel, Table of n, a(n) for n = 0..895 FORMULA a(0)=1, a(1)=1, a(n) = a(n-1) - floor(n/2)*a(n-2). MAPLE a:= proc(n) option remember;    if n<2 then 1    else a(n-1) - floor(n/2)*a(n-2)    fi; end: seq(a(n), n=0..40); # G. C. Greubel, Dec 05 2019 MATHEMATICA a[n_]:= a[n]= If[n<2, 1, a[n-1] -Floor[n/2]*a[n-2]]; Table[a[n], {n, 0, 40}] (* G. C. Greubel, Dec 05 2019 *) PROG (PARI) a(n) = if(n<2, n, a(n-1) - (n\2)*a(n-2) ); \\ G. C. Greubel, Dec 05 2019 (MAGMA) function a(n)   if n lt 2 then return 1;   else return a(n-1) - Floor(n/2)*a(n-2);   end if; return a; end function; [a(n): n in [0..40]]; // G. C. Greubel, Dec 05 2019 (Sage) @CachedFunction def a(n):     if (n<2): return 1     else: return a(n-1) - floor(n/2)*a(n-2) [a(n) for n in (0..40)] # G. C. Greubel, Dec 05 2019 (GAP) a:= function(n)     if n<2 then return 1;     else return a(n-1) - Int(n/2)*a(n-2);     fi; end; List([0..40], n-> a(n) ); # G. C. Greubel, Dec 05 2019 CROSSREFS Sequence in context: A159764 A124029 A207823 * A123382 A197653 A146160 Adjacent sequences:  A056917 A056918 A056919 * A056921 A056922 A056923 KEYWORD sign,frac,easy AUTHOR Aleksandar Petojevic (apetoje(AT)ptt.yu), Sep 05 2000 EXTENSIONS More terms from James A. Sellers, Sep 06 2000 STATUS approved

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Last modified February 28 06:55 EST 2020. Contains 332321 sequences. (Running on oeis4.)