a(n) = 3*a(n-1)+4 for n > 0; a(0) = 6.

Terms

a(0) =6a(1) =22a(2) =70a(3) =214a(4) =646a(5) =1942a(6) =5830a(7) =17494a(8) =52486a(9) =157462a(10) =472390a(11) =1417174a(12) =4251526a(13) =12754582a(14) =38263750a(15) =114791254a(16) =344373766a(17) =1033121302a(18) =3099363910a(19) =9298091734a(20) =27894275206a(21) =83682825622a(22) =251048476870a(23) =753145430614