

A233820


Period 4: repeat [20, 5, 15, 10].


0



20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5, 15, 10, 20, 5
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

Clockwise sectors around outside of London Fives dartboard.


LINKS



FORMULA

G.f.: 5*x*(4 + x + 3*x^2 + 2*x^3)/((1  x)*(1 + x)*(1 + x^2)).
a(n) = 5*(I^(n*(n1))  2*(1)^n + 5)/2. (End)
a(n) = 5*(5 + cos(n*Pi/2)  2*cos(n*Pi) + sin(n*Pi/2)  2*I*sin(n*Pi))/2.
a(n) = a(n4) for n>4. (End)


MAPLE



MATHEMATICA

Flatten[Table[{20, 5, 15, 10}, {17}]]


PROG

(Magma) &cat[[20, 5, 15, 10]: n in [1..17]]; // Bruno Berselli, Dec 16 2013


CROSSREFS



KEYWORD

nonn,easy


AUTHOR



STATUS

approved



