a(n) = Lucas(4n+2)+2, or 5*Fibonacci(2n+1)^2.

A081067

a(n) = Lucas(4n+2)+2, or 5*Fibonacci(2n+1)^2.

Terms

    a(0) =5a(1) =20a(2) =125a(3) =845a(4) =5780a(5) =39605a(6) =271445a(7) =1860500a(8) =12752045a(9) =87403805a(10) =599074580a(11) =4106118245a(12) =28143753125a(13) =192900153620

External references