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A281482 a(n) = 2^(n + 1) * (2^n + 1) - 1.

%I A281482 #18 May 02 2025 16:23:33
%S A281482 3,11,39,143,543,2111,8319,33023,131583,525311,2099199,8392703,
%T A281482 33562623,134234111,536903679,2147549183,8590065663,34360000511,
%U A281482 137439477759,549756862463,2199025352703,8796097216511,35184380477439,140737505132543,562949986975743
%N A281482 a(n) = 2^(n + 1) * (2^n + 1) - 1.
%H A281482 Colin Barker, <a href="/A281482/b281482.txt">Table of n, a(n) for n = 0..1000</a>
%H A281482 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (7,-14,8).
%F A281482 From _Colin Barker_, Jan 22 2017: (Start)
%F A281482 a(n) = 7*a(n-1) - 14*a(n-2) + 8*a(n-3) for n>2.
%F A281482 G.f.: (3 - 10*x + 4*x^2) / ((1 - x)*(1 - 2*x)*(1 - 4*x)).
%F A281482 (End)
%o A281482 (Magma) [2^(n + 1) * (2^n + 1) - 1: n in [0..200]];
%o A281482 (PARI) Vec((3 - 10*x + 4*x^2) / ((1 - x)*(1 - 2*x)*(1 - 4*x)) + O(x^30)) \\ _Colin Barker_, Jan 22 2017
%Y A281482 Similar sequences: A085601 (2^(n + 1) * (2^n + 1) + 1), A092431 (2^(n - 1) * (2^n + 1) - 1), A092440 (2^(n + 1) * (2^n - 1) + 1), A129868 (2^(n - 1) * (2^n - 1) - 1), A134169 (2^(n - 1) * (2^n - 1) + 1), A267816 (2^(n + 1) * (2^n - 1) - 1), A281481 (2^(n - 1) * (2^n + 1) + 1).
%K A281482 nonn,easy
%O A281482 0,1
%A A281482 _Jaroslav Krizek_, Jan 22 2017