a(0)=2, a(1)=2, a(n) = 2*a(n-1) + 12*a(n-2).

Terms

a(0) =2a(1) =2a(2) =28a(3) =80a(4) =496a(5) =1952a(6) =9856a(7) =43136a(8) =204544a(9) =926720a(10) =4307968a(11) =19736576a(12) =91168768a(13) =419176448a(14) =1932378112a(15) =8894873600a(16) =40978284544a(17) =188695052288a(18) =869129519104