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%I #14 Oct 19 2017 03:14:04
%S 15,45,117,213,-171,-4779,-35499,-207531,-1092267,-5417643,-25864875,
%T -120236715,-548055723,-2460658347,-10916375211,-47960468139,
%U -209021741739,-904806443691,-3894103681707,-16675926354603,-71101751929515,-301999193762475,-1278365519227563
%N (3*a(n)+1)/2^(2*n + 1) = 23-6*n.
%C Related to the Collatz conjecture.
%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (9, -24, 16).
%F a(n) = ((46-12*n)*4^n-1)/3. - _Don Reble_, Oct 31 2005
%F a(0)=15, a(1)=45, a(2)=117, a(n)=9*a(n-1)-24*a(n-2)+16*a(n-3). - _Harvey P. Dale_, Sep 14 2012
%F G.f.: ( -15+90*x-72*x^2 ) / ( (x-1)*(-1+4*x)^2 ). - _R. J. Mathar_, Nov 07 2015
%t Table[((46-12n)4^n-1)/3,{n,0,30}] (* or *) LinearRecurrence[{9,-24,16},{15,45,117},40] (* _Harvey P. Dale_, Sep 14 2012 *)
%K sign,easy,less
%O 0,1
%A N. Rathankar (rathankar(AT)yahoo.com), Jul 08 2002
%E Edited and extended by _David Wasserman_, Dec 27 2006
%E Corrected by _N. J. A. Sloane_, Mar 01 2007
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