login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A171445 Sequence whose G.f is given by f(z)=(1+z)^(24)/(1-z). 0
1, 25, 301, 2325, 12951, 55455, 190051, 536155, 1271626, 2579130, 4540386, 7036530, 9740686, 12236830, 14198086, 15505590, 16241061, 16587165, 16721761, 16764265, 16774891, 16776915, 16777191, 16777215, 16777216, 16777216 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

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

REFERENCES

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

LINKS

Table of n, a(n) for n=0..25.

FORMULA

With m=25, a(n)=sum(C(m,n-2*k),k=0..floor(n/2)).

EXAMPLE

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

MAPLE

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);

MATHEMATICA

CoefficientList[Series[(1+x)^24/(1-x), {x, 0, 30}], x] (* Harvey P. Dale, Jun 11 2019 *)

CROSSREFS

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

Sequence in context: A042206 A269448 A128377 * A264274 A278876 A053805

Adjacent sequences:  A171442 A171443 A171444 * A171446 A171447 A171448

KEYWORD

easy,nonn

AUTHOR

Richard Choulet, Dec 09 2009

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 13 22:25 EDT 2019. Contains 327983 sequences. (Running on oeis4.)