OFFSET
1,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (10,25,-250,-125,1250).
FORMULA
Consider the 5/5Z addition table considered as matrix X = [0,1,2,3,4; 1,2,3,4,0; 2,3,4,0,1; 3,4,0,1,2; 4,0,1,2,3]. Then a(n) = term (1,2) of X^n.
G.f.: -x*(25*x^3-50*x^2+10*x+1) / ((10*x-1)*(125*x^4-25*x^2+1)). - Colin Barker, May 25 2013
EXAMPLE
a(5) = 19500 since term (1,2) of X^5 = 19500.
MAPLE
a:= n-> (Matrix(5, (i, j)-> irem(i+j-2, 5))^n)[1, 2]:
seq(a(n), n=1..25); # Alois P. Heinz, May 25 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Gary W. Adamson and Roger L. Bagula, May 02 2008
EXTENSIONS
Two terms corrected and more terms added by Colin Barker, May 25 2013
STATUS
approved