a(n) = 4*a(n-1) - 5*a(n-2).

Terms

a(0) =2a(1) =6a(2) =14a(3) =26a(4) =34a(5) =6a(6) =-146a(7) =-614a(8) =-1726a(9) =-3834a(10) =-6706a(11) =-7654a(12) =2914a(13) =49926a(14) =185134a(15) =490906a(16) =1037954a(17) =1697286a(18) =1599374a(19) =-2088934a(20) =-16352606a(21) =-54965754a(22) =-138099986a(23) =-277571174a(24) =-419784766a(25) =-291283194a(26) =933791054a(27) =5191580186a(28) =16097365474a(29) =38431560966