12586269026domain: NAppears in sequencesExpansion of (2-6*x+4*x^2-x^3)/((1-x)*(1-3*x+x^2)).at n=25A052925a(n) = 3*a(n-1) - a(n-2) - 1 with a(0) = 1 and a(1) = 2.at n=25A055588a(n) = Fibonacci(4n+2) + 1, or Fibonacci(2n+2)*Lucas(2n).at n=12A081004a(n) = F(n)*L(n-2) where F = Fibonacci and L = Lucas numbers.at n=26A128535