a(n) = 3a(n-1) + 4a(n-2), a(0) = 1, a(1) = 5.

Terms

a(0) =1a(1) =5a(2) =19a(3) =77a(4) =307a(5) =1229a(6) =4915a(7) =19661a(8) =78643a(9) =314573a(10) =1258291a(11) =5033165a(12) =20132659a(13) =80530637a(14) =322122547a(15) =1288490189a(16) =5153960755a(17) =20615843021a(18) =82463372083a(19) =329853488333