a(n) = Lucas(4n) - 3, or Lucas(2n-1)*Lucas(2n+1).

A081078

a(n) = Lucas(4n) - 3, or Lucas(2n-1)*Lucas(2n+1).

Terms

    a(0) =4a(1) =44a(2) =319a(3) =2204a(4) =15124a(5) =103679a(6) =710644a(7) =4870844a(8) =33385279a(9) =228826124a(10) =1568397604a(11) =10749957119a(12) =73681302244a(13) =505019158604

External references