OFFSET
1,1
COMMENTS
First differences of A338225.
Also it is second differences between the areas of consecutive rectangles with side lengths F(n+3) and F(n).
REFERENCES
Burak Muslu, Sayılar ve Bağlantılar, Luna, 2021, p. 51.
LINKS
FORMULA
a(n) = F(n+4) * F(n+1) - 4 * (-1)^n for n > 0.
G.f.: x*(9 - 6*x + x^2)/(1 - 2*x - 2*x^2 + x^3).
EXAMPLE
For n = 2, a(2) = F(2+4) * F(2+1) - 4 * (-1)^2 = 8 * 2 - 4 = 12.
PROG
(PARI) a(n) = fibonacci(n+4)*fibonacci(n+1) - 4*(-1)^n; \\ Michel Marcus, Feb 06 2021
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Burak Muslu, Feb 06 2021
STATUS
approved