a(n) = 3*a(n-1) + 10*a(n-2), n >= 2; a(0)=1, a(1)=1.

Terms

a(0) =1a(1) =1a(2) =13a(3) =49a(4) =277a(5) =1321a(6) =6733a(7) =33409a(8) =167557a(9) =836761a(10) =4185853a(11) =20925169a(12) =104634037a(13) =523153801a(14) =2615801773a(15) =13078943329a(16) =65394847717a(17) =326973976441