a(1) = 6; a(n+1) = (a(n)+1)/2 if a(n) odd, or 5*a(n)/2 if a(n) even.

Terms

a(0) =6a(1) =15a(2) =8a(3) =20a(4) =50a(5) =125a(6) =63a(7) =32a(8) =80a(9) =200a(10) =500a(11) =1250a(12) =3125a(13) =1563a(14) =782a(15) =1955a(16) =978a(17) =2445a(18) =1223a(19) =612a(20) =1530a(21) =3825a(22) =1913a(23) =957a(24) =479a(25) =240a(26) =600a(27) =1500a(28) =3750a(29) =9375