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%I #20 Aug 18 2021 06:56:27
%S 1,5,7,19,25,77,103,307,409,1229,1639,4915,6553,19661,26215,78643,
%T 104857,314573,419431,1258291,1677721,5033165,6710887,20132659,
%U 26843545,80530637,107374183,322122547,429496729,1288490189,1717986919,5153960755
%N The subsequence A247649(2^n-1).
%C Note that A247649 is not the Run Length Transform of this sequence - compare A253085.
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,3,0,4)
%F G.f.: (1+5*x+4*x^2+4*x^3)/(1-3*x^2-4*x^4).
%t LinearRecurrence[{0,3,0,4}, {1,5,7,19}, 40] (* _Georg Fischer_, Aug 18 2021 *)
%Y Cf. A247649, A253085.
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_, Mar 03 2015