OFFSET
0,2
LINKS
E. Barcucci, R. Pinzani and R. Sprugnoli, Directed column-convex polyominoes by recurrence relations, Lecture Notes in Computer Science, No. 668, Springer, Berlin (1993), pp. 282-298.
Index entries for linear recurrences with constant coefficients, signature (5,-8,5,-1).
FORMULA
a(n) = Fibonacci(2*n) + Fibonacci(2*n+2) - n = A002878(n)-n.
G.f.: (1-2x+2x^2)/((1-x)^2(1-3x+x^2)).
a(n) = 5*a(n-1) - 8*a(n-2) + 5*a(n-3) - a(n-4) for n >= 4. - Jinyuan Wang, Mar 10 2020
PROG
(PARI) Vec((1-2*x+2*x^2)/((1-x)^2*(1-3*x+x^2)) + O(x^40)) \\ Michel Marcus, Feb 14 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Emeric Deutsch, Jun 16 2001
STATUS
approved