Fourth line of 5-wave sequence A038201.

Terms

a(0) =1a(1) =2a(2) =14a(3) =29a(4) =175a(5) =365a(6) =2163a(7) =4516a(8) =26703a(9) =55759a(10) =329615a(11) =688286a(12) =4068623a(13) =8495917a(14) =50221212a(15) =104869718a(16) =619907431a(17) =1294463368a(18) =7651850657a(19) =15978257251a(20) =94450905714a(21) =197228218022