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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A094788 Number of (s(0), s(1), ..., s(2n+1)) such that 0 < s(i) < 10 and |s(i) - s(i-1)| = 1 for i = 1,2,....,2n+1, s(0) = 1, s(2n+1) = 6. 2
1, 6, 27, 110, 428, 1624, 6069, 22458, 82555, 302082, 1101816, 4009616, 14567657, 52865230, 191684283, 694609494, 2515972324, 9110338728, 32981059485, 119377761602, 432046756571, 1563510554986, 5657752486512, 20472344560800 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

COMMENTS

Diagonal of the square array A217593. - Philippe Deléham, Mar 28 2013

LINKS

Table of n, a(n) for n=2..25.

FORMULA

a(n) = (1/5)*sum(r=1..9, sin(r*Pi/10)*sin(3*r*Pi/5)*(2*cos(r*Pi/10))^(2*n+1)).

a(n) = 8*a(n-1) - 21*a(n-2) + 20*a(n-3) - 5*a(n-4).

G.f.: x^2*(1-2*x)/(1-8*x+21*x^2-20*x^3+5*x^4).

a(n+2) = A217593(n,n+5). - Philippe Deléham, Mar 28 2013

PROG

(PARI) Vec(x^2*(1-2*x)/(1-8*x+21*x^2-20*x^3+5*x^4)+O(x^66)) /* Joerg Arndt, Mar 29 2013 */

CROSSREFS

Sequence in context: A055145 A037604 A022634 * A221863 A216263 A003517

Adjacent sequences:  A094785 A094786 A094787 * A094789 A094790 A094791

KEYWORD

nonn

AUTHOR

Herbert Kociemba, Jun 15 2004

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 23 12:50 EST 2018. Contains 299581 sequences. (Running on oeis4.)