login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 


a(n) = T(2n,n-3), T given by A026725.
4

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

%S 1,9,56,300,1487,7041,32381,146017,649395,2859231,12494914,54291912,

%T 234860677,1012433965,4352210327,18666918033,79916230409,341615895659,

%U 1458457275715,6220016154525,26503542364381,112847001503099,480173686483581

%N a(n) = T(2n,n-3), T given by A026725.

%C Column k=8 of triangle A236830. - _Philippe Deléham_, Feb 02 2014

%H G. C. Greubel, <a href="/A026842/b026842.txt">Table of n, a(n) for n = 3..1000</a>

%F a(n) = A026846(n) = A026849(n). - _Philippe Deléham_, Feb 02 2014

%F G.f.: (x^3*C(x)^8)/(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])^8/(32*x^3*(8*x^2 -(1 - Sqrt[1-4*x])^3 )), {x,0,30}], x],3] (* _G. C. Greubel_, Jul 17 2019 *)

%o (PARI) my(x='x+O('x^30)); Vec((1-sqrt(1-4*x))^8/(32*x^3*(8*x^2 -(1 - sqrt(1-4*x))^3 ))) \\ _G. C. Greubel_, Jul 17 2019

%o (Magma) R<x>:=PowerSeriesRing(Rationals(), 30); Coefficients(R!( (1-Sqrt(1-4*x))^8/(32*x^3*(8*x^2 -(1-Sqrt(1-4*x))^3 )) )); // _G. C. Greubel_, Jul 17 2019

%o (Sage) a=((1-sqrt(1-4*x))^8/(32*x^3*(8*x^2 -(1-sqrt(1-4*x))^3 ))).series(x, 30).coefficients(x, sparse=False); a[3:] # _G. C. Greubel_, Jul 17 2019

%Y Cf. A236830, A026846, A026849.

%K nonn

%O 3,2

%A _Clark Kimberling_

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 21 08:46 EDT 2024. Contains 376084 sequences. (Running on oeis4.)