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A171445 Expansion of g.f. (1+z)^(24)/(1-z). 0

%I #16 Jun 23 2023 18:23:08

%S 1,25,301,2325,12951,55455,190051,536155,1271626,2579130,4540386,

%T 7036530,9740686,12236830,14198086,15505590,16241061,16587165,

%U 16721761,16764265,16774891,16776915,16777191,16777215,16777216,16777216

%N Expansion of g.f. (1+z)^(24)/(1-z).

%C a(n)=2^(24)=16777216 for n>=24. We observe that this sequence is the transform of A171443 by the iterated T^(16) of 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,...).

%H Richard Choulet, <a href="https://mp.sbpm.be/MP157.PDF">Une nouvelle formule de combinatoire?</a>, Mathématique et Pédagogie, 157 (2006), p. 53-60. In French.

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

%F With m=25, a(n) = Sum_{k=0..floor(n/2)} binomial(m,n-2*k).

%e a(3) = C(25,3)+C(25,3-2) = 2325.

%p m:=25: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)^24/(1-x),{x,0,30}],x] (* _Harvey P. Dale_, Jun 11 2019 *)

%Y Cf. A040000, A113311, A115291, A171418, A171440, A171441, A171442, A171443.

%K easy,nonn

%O 0,2

%A _Richard Choulet_, Dec 09 2009

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Last modified March 29 08:13 EDT 2024. Contains 371265 sequences. (Running on oeis4.)