OFFSET
0,2
LINKS
FORMULA
G.f.: (1-4*x)/(1-10*x+20*x^2) = (1-4*x)/((1-(5-sqrt(5))*x)*(1-(5+sqrt(5))*x)).
E.g.f.: exp(5*x)*(cosh(sqrt(5)*x) + sinh(sqrt(5)*x)/sqrt(5));
a(n) = ((1+sqrt(5))*(5+sqrt(5))^n - (1-sqrt(5))*(5-sqrt(5))^n)/(2*sqrt(5)).
Fifth binomial transform of (1, 1, 5, 5, 25, 25, ...). - Paul Barry, Nov 22 2003
3rd binomial transform of Fibonacci(3n+1). - Paul Barry, Mar 23 2004
a(n) = Sum_{k=0..n} A117317(n,k)*4^k. - Philippe Deléham, Jan 28 2012
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Nov 20 2003
STATUS
approved