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a(n) = T(2n,n-4), T given by A026736.
3

%I #13 Sep 08 2022 08:44:49

%S 1,11,79,471,2535,12809,62067,292085,1345718,6102780,27343148,

%T 121359692,534632836,2341151646,10201950700,44278673806,191540714294,

%U 826265471868,3555992623850,15273547250820,65491352071266,280412963707416

%N a(n) = T(2n,n-4), T given by A026736.

%C Is this the same as A026841? - _R. J. Mathar_, Oct 23 2008

%C Column k=10 of triangle A236830. - _Philippe Deléham_, Feb 02 2014

%H G. C. Greubel, <a href="/A026848/b026848.txt">Table of n, a(n) for n = 4..1000</a>

%F a(n) = A026841(n). - _Philippe Deléham_, Feb 02 2014

%F G.f.: (x^4*C(x)^10)/(1-x*C(x)^3) where C(x) is the g.f. of A000108. - _Philippe Deléham_, Feb 02 2014

%t Drop[CoefficientList[Series[(1-Sqrt[1-4*x])^10/(128*x^4*(8*x^2 -(1 - Sqrt[1-4*x])^3 )), {x,0,40}], x], 4] (* _G. C. Greubel_, Jul 17 2019 *)

%o (PARI) my(x='x+O('x^40)); Vec((1-sqrt(1-4*x))^10/(128*x^4*(8*x^2 -(1 - sqrt(1-4*x))^3 ))) \\ _G. C. Greubel_, Jul 17 2019

%o (Magma) R<x>:=PowerSeriesRing(Rationals(), 40); Coefficients(R!( (1-Sqrt(1-4*x))^10/(128*x^4*(8*x^2 -(1-Sqrt(1-4*x))^3 )) )); // _G. C. Greubel_, Jul 17 2019

%o (Sage) a=((1-sqrt(1-4*x))^10/(128*x^4*(8*x^2 -(1-sqrt(1-4*x))^3 ))).series(x, 45).coefficients(x, sparse=False); a[4:40] # _G. C. Greubel_, Jul 17 2019

%Y Cf. A236830.

%K nonn

%O 4,2

%A _Clark Kimberling_