Least k such that A020951(k) = n.

Terms

a(0) =0a(1) =10a(2) =20a(3) =40a(4) =42a(5) =160a(6) =82a(7) =84a(8) =162a(9) =166a(10) =164a(11) =172a(12) =170a(13) =324a(14) =328a(15) =348a(16) =332a(17) =330a(18) =338a(19) =700a(20) =340a(21) =652a(22) =650a(23) =664a(24) =662a(25) =658a(26) =666a(27) =1290a(28) =660a(29) =676