866988873domain: NAppears in sequencesa(n) = 2*Fibonacci(2*n+1) - 1.at n=21A069403Expansion of (-1-x-x^2-4*x^3-4*x^4+4*x^5+x^6+x^7+x^8) / ((x+1)*(x^2-x+1)*(x^2+x-1)*(x^4-x^3+2*x^2+x+1)).at n=42A108390Expansion of (-1-x-x^2-4*x^3-4*x^4+4*x^5+x^6+x^7+x^8) / ((x+1)*(x^2-x+1)*(x^2+x-1)*(x^4-x^3+2*x^2+x+1)).at n=43A108390