a(n) = 8*a(n-1) - a(n-2); a(0) = 1, a(1) = 4.

A001091

a(n) = 8*a(n-1) - a(n-2); a(0) = 1, a(1) = 4.

Terms

    a(0) =1a(1) =4a(2) =31a(3) =244a(4) =1921a(5) =15124a(6) =119071a(7) =937444a(8) =7380481a(9) =58106404a(10) =457470751a(11) =3601659604a(12) =28355806081a(13) =223244789044

External references