

A171418


Expansion of (1+x)^4/(1x).


10



1, 5, 11, 15, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,2


COMMENTS

For n>=4 a(n)=2^4=16. This sequence is the transform of A115291 by the following transform T: T(u_0,u_1,u_2,u_3,u_4,...)=(u_0,u_0+u_1, u_1+u_2,u_2+u_3,aso); we observe that T(A040000)=A113311 and also T(A113311)=A115291...
Also continued fraction expansion of (55305+sqrt(65))/46231.  Bruno Berselli, Sep 23 2011


REFERENCES

(Revue) Richard Choulet, Une nouvelle formule de combinatoire?, Mathematique et Pedagogie, 157(2006), p. 5360.


LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (1).


FORMULA

a(n) = sum(C(5,n2*k),k=0..floor(n/2)).


EXAMPLE

a(3)=C(5,30)+C(5,32)=10+5=15.


MAPLE

m:=5:for n from 0 to m+1 do a(n):=sum('binomial(m, n2*k)', k=0..floor(n/2)): od : seq(a(n), n=0..m+1);


CROSSREFS

Cf. A040000, A113311, A115291, A171440, A171441, A171442, A171443.
Sequence in context: A137002 A091718 A078002 * A213444 A137004 A137005
Adjacent sequences: A171415 A171416 A171417 * A171419 A171420 A171421


KEYWORD

nonn,easy


AUTHOR

Richard Choulet, Dec 08 2009


EXTENSIONS

Definition rewritten by Bruno Berselli, Sep 23 2011


STATUS

approved



