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 A171443 Expansion of (1+x)^8/(1-x). 9

%I

%S 1,9,37,93,163,219,247,255,256,256,256,256,256,256,256,256,256,256,

%T 256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,

%U 256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256

%N Expansion of (1+x)^8/(1-x).

%C a(n)=2^8=256 for n>=8. We observe that this sequence is the transform of A171442 by T such that: T(u_0,u_1,u_2,u_3,u_4,u_5,...)=(u_0,u_0+u_1,u_1+u_2,u_2+u_3,u_3+u_4,...).

%D Richard Choulet, Une nouvelle formule de combinatoire, Mathematique et Pedagogie, 157 (2006), p. 53-60.

%H Vincenzo Librandi, <a href="/A171443/b171443.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (1).

%F With m=9, a(n)=sum(C(m,n-2*k),k=0..floor(n/2)).

%e a(7) = C(9,7-0)+C(9,7-2)+C(9,7-4)+C(9,7-6) = 36+126+84+9 = 255.

%p m:=9:for n from 0 to 40 do a(n):=sum('binomial(m,n-2*k)',k=0..floor(n/2)): od : seq(a(n),n=0..40);

%t CoefficientList[Series[(1+x)^8/(1-x),{x,0,80}],x] (* _Harvey P. Dale_, Jul 22 2014 *)

%Y Cf. A040000, A113311, A115291, A171418, A171440, A171441, A171442.

%K nonn,easy

%O 0,2

%A _Richard Choulet_, Dec 09 2009

%E Definition rewritten by _Bruno Berselli_, Sep 23 2011

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Last modified October 14 03:58 EDT 2019. Contains 327995 sequences. (Running on oeis4.)