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%I #10 Feb 02 2020 22:23:38
%S 0,-3,3,9,-6,3,117,-249,-21,1917,-237,-9111,1287,24963,-76443,28071,
%T 11067,-848643,-922077,6087369,-184623,-27482877,34867797,67678791,
%U -15126111,145641597,1064447283,-2857102551,-308141733,19215780483,-6890111163
%N Numerator of imaginary part of (2*omega)^(-n) where omega = (-1 + i*3)/ 2.
%H Robert Israel, <a href="/A124871/b124871.txt">Table of n, a(n) for n = 0..2859</a>
%F a(n) = numerator(Im(1/(-1 + i*3)^n) ). 1/(-1 + i*3)^n = A124869(n)/ A124870(n) + i*A124871(n)/A124872(n).
%e a(0) = 0 = numerator of Im((-1+3*i)^0) = 1/1 + 0*i.
%e a(1) = -3 = numerator of Im(1/(-1+3*i)) = -1/10 - i*3/10.
%e a(2) = 3 = numerator of Im((-1+3*i)^(-2)) = -2/25 + i*3/50.
%e a(3) = 9 = numerator of Im((-1+3*i)^(-3)) = 13/500 + i*9/500.
%e a(4) = -6 = numerator of Im((-1+3*i)^(-4)) = 7/2500 - i*6/625.
%e a(5) = 3 = numerator of Im((-1+3*i)^(-5)) = -79/25000 + i*3/25000.
%e a(6) = 117 = numerator of Im((-1+3*i)^(-6)) = 11/31250 + i*117/125000.
%e a(7) = -249 = numerator of Im((-1+3*i)^(-7)) = 307/1250000 - i*249/1250000.
%e a(8) = -21 = numerator of Im((-1+3*i)^(-8)) = -527/6250000 - i*21/390625.
%p B:= gfun:-rectoproc({-10*b(x + 2) - 2*b(x + 1) - b(x), b(0) = 0, b(1) = -3/10},b(x),remember):
%p map(numer,[seq(B(n),n=0..50)]); # _Robert Israel_, Feb 02 2020
%Y Cf. A124869-A124872.
%K easy,frac,sign
%O 0,2
%A _Jonathan Vos Post_, Nov 11 2006
%E Removed square roots from definition and formula. - _R. J. Mathar_, May 02 2009
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