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%I #14 Jun 29 2023 16:23:33
%S 1,5,13,28,58,118,238,478,958,1918,3838,7678,15358,30718,61438,122878,
%T 245758,491518,983038,1966078,3932158,7864318,15728638,31457278,
%U 62914558,125829118,251658238,503316478,1006632958,2013265918
%N a(0) = 1, a(1) = 5, a(2) = 13; a(n) = 2*a(n-1) + 2, n > 2.
%C Sometimes confused with A002717.
%H Harry J. Smith, <a href="/A060182/b060182.txt">Table of n, a(n) for n = 0..200</a>
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (3, -2).
%F a(n) = 3(a(n-1) - a(n-2) + a(n-3) - ... ((-1)^(n+1))*a(0))+1;
%F a(n) = (2^(n-3))*a(3) + (2^(n-2)) - 2 for n > 3.
%F From _R. J. Mathar_, Jul 15 2009: (Start)
%F G.f.: -(1+x)*(x^2-x-1)/((-1+x)*(-1+2*x)).
%F a(n) = 15*2^(n-2) - 2, n > 1. (End)
%o (PARI) { a=-1; for (n=0, 200, a=2*a + 2; if (n<3, a++); write("b060182.txt", n, " ", a); ) } \\ _Harry J. Smith_, Jul 02 2009
%K nonn,easy
%O 0,2
%A Brian Wallace (wallacebrianedward(AT)yahoo.co.uk), Mar 19 2001
%E Simpler formula and more terms from Larry Reeves (larryr(AT)acm.org), Mar 30 2001
%E Edited by _N. J. A. Sloane_ at the suggestion of Philippe LALLOUET (philip.lallouet(AT)wanadoo.fr), Sep 16 2007
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