a(n) = 3*a(n-1)+n if a(n-1) is not divisible by 2, or a(n) = a(n-1)/2 otherwise.

Terms

a(0) =1a(1) =4a(2) =2a(3) =1a(4) =7a(5) =26a(6) =13a(7) =46a(8) =23a(9) =78a(10) =39a(11) =128a(12) =64a(13) =32a(14) =16a(15) =8a(16) =4a(17) =2a(18) =1a(19) =22a(20) =11a(21) =54a(22) =27a(23) =104a(24) =52a(25) =26a(26) =13a(27) =66a(28) =33a(29) =128