cp's OEIS Frontend

A026633 a(n) = Sum_{k=0..n} A026626(n, k).

%I A026633 #19 Jun 21 2024 03:23:21
%S A026633 1,2,5,10,22,44,90,180,362,724,1450,2900,5802,11604,23210,46420,92842,
%T A026633 185684,371370,742740,1485482,2970964,5941930,11883860,23767722,
%U A026633 47535444,95070890,190141780,380283562,760567124,1521134250
%N A026633 a(n) = Sum_{k=0..n} A026626(n, k).
%H A026633 G. C. Greubel, <a href="/A026633/b026633.txt">Table of n, a(n) for n = 0..1000</a>
%H A026633 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (2,1,-2).
%F A026633 G.f.: (1+x^4)/((1-2*x)*(1-x^2)). - _Ralf Stephan_, Apr 30 2004
%F A026633 a(n) = (1/3)*(17*2^(n-2) + (-1)^n) - 1, n>=2. - _R. J. Mathar_, May 22 2013
%F A026633 a(n) = a(n-1) + 2*a(n-2) + 2. - _Greg Dresden_, Feb 22 2020
%F A026633 E.g.f.: (3 + 6*x - 8*cosh(x) + 17*cosh(2*x) - 16*sinh(x) + 17*sinh(2*x))/12. - _Stefano Spezia_, Feb 22 2020
%t A026633 Table[(17*2^(n-2) +(-1)^n)/3 -1 +Boole[n==0]/4 +Boole[n==1]/2, {n, 0, 40}] (* _G. C. Greubel_, Jun 21 2024 *)
%o A026633 (Magma) [n le 1 select n+1 else (17*2^(n-2) +(-1)^n)/3 -1: n in [0..40]]; // _G. C. Greubel_, Jun 21 2024
%o A026633 (SageMath) [(17*2^(n-2) +(-1)^n)/3 -1 +int(n==0)/4 +int(n==1)/2 for n in range(41)] # _G. C. Greubel_, Jun 21 2024
%Y A026633 Row sums of A026626.
%Y A026633 Cf. A026627, A026628, A026629, A026630, A026631, A026632, A026634.
%Y A026633 Cf. A026635, A026636, A026961, A026962, A026963, A026964, A026965.
%K A026633 nonn
%O A026633 0,2
%A A026633 _Clark Kimberling_