OFFSET
1,1
COMMENTS
Linear recurrence and empirical g.f. confirmed by more terms. - Ray Chandler, Mar 07 2024
LINKS
Ray Chandler, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (35, -383, 1465, -1516, 80).
FORMULA
a(n)=(1/4)*(F(6n-3)+4^n*F(2n-1)+2*5^(n-1))
Empirical G.f.: -x*(68*x^4-597*x^3+346*x^2-51*x+2) / ((5*x-1)*(x^2-18*x+1)*(16*x^2-12*x+1)). [Colin Barker, Dec 01 2012]
PROG
(PARI) a(n)=(1/4)*(fibonacci(6*n-3)+4^n*fibonacci(2*n-1)+2*5^(n-1))
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Nov 29 2006
STATUS
approved