Trajectory of 7 under map x --> x + (x-with-digits-reversed).

Terms

a(0) =7a(1) =14a(2) =55a(3) =110a(4) =121a(5) =242a(6) =484a(7) =968a(8) =1837a(9) =9218a(10) =17347a(11) =91718a(12) =173437a(13) =907808a(14) =1716517a(15) =8872688a(16) =17735476a(17) =85189247a(18) =159487405a(19) =664272356a(20) =1317544822a(21) =3602001953a(22) =7193004016a(23) =13297007933a(24) =47267087164a(25) =93445163438a(26) =176881317877a(27) =955594506548