a(n) = 3*a(n-1) - 2*a(n-2) with a(0)=16 and a(1)=40.

Terms

a(0) =16a(1) =40a(2) =88a(3) =184a(4) =376a(5) =760a(6) =1528a(7) =3064a(8) =6136a(9) =12280a(10) =24568a(11) =49144a(12) =98296a(13) =196600a(14) =393208a(15) =786424a(16) =1572856a(17) =3145720a(18) =6291448a(19) =12582904a(20) =25165816a(21) =50331640a(22) =100663288a(23) =201326584a(24) =402653176a(25) =805306360a(26) =1610612728a(27) =3221225464a(28) =6442450936a(29) =12884901880