a(n) = 3*a(n-1) + 7*a(n-2), with a(1) = 1, a(2) = 10.

Terms

a(0) =1a(1) =10a(2) =37a(3) =181a(4) =802a(5) =3673a(6) =16633a(7) =75610a(8) =343261a(9) =1559053a(10) =7079986a(11) =32153329a(12) =146019889a(13) =663132970a(14) =3011538133a(15) =13676545189a(16) =62110402498a(17) =282067023817