a(n) gives smallest number requiring n iterations of the map i -> A053392(i) to reach zero.

Terms

a(0) =0a(1) =1a(2) =10a(3) =19a(4) =109a(5) =149a(6) =197a(7) =399a(8) =694a(9) =796a(10) =893a(11) =897a(12) =1167a(13) =1579a(14) =1596a(15) =1667a(16) =1790a(17) =1777a(18) =2859a(19) =1779a(20) =1778a(21) =1873a(22) =3679a(23) =5926a(24) =11289a(25) =9539a(26) =13551a(27) =4589a(28) =5960a(29) =12066