Analog of A006684 for the 7x+1 problem (cf. A133421).

Terms

a(0) =1a(1) =7a(2) =11a(3) =19a(4) =31a(5) =43a(6) =163a(7) =283a(8) =403a(9) =1111a(10) =1123a(11) =1243a(12) =1303a(13) =1549a(14) =1963a(15) =4123a(16) =9643a(17) =10003a(18) =11539a(19) =21431a(20) =76963a(21) =97031a(22) =468109a(23) =1351963a(24) =4553323a(25) =4778471a(26) =5163139a(27) =6563551a(28) =7618843a(29) =45214123