a(n) = a(n-1) + 5*a(n-2), with a(0) = a(1) = 1.

Terms

a(0) =1a(1) =1a(2) =6a(3) =11a(4) =41a(5) =96a(6) =301a(7) =781a(8) =2286a(9) =6191a(10) =17621a(11) =48576a(12) =136681a(13) =379561a(14) =1062966a(15) =2960771a(16) =8275601a(17) =23079456a(18) =64457461a(19) =179854741a(20) =502142046a(21) =1401415751a(22) =3912125981a(23) =10919204736a(24) =30479834641a(25) =85075858321a(26) =237475031526a(27) =662854323131