Smallest k for which A389781(k) = n.

Terms

a(0) =1a(1) =2a(2) =12a(3) =6a(4) =30a(5) =42a(6) =273a(7) =330a(8) =510a(9) =210a(10) =2310a(11) =7854a(12) =14790a(13) =36465a(14) =39270a(15) =46410a(16) =60060a(17) =465465a(18) =570570a(19) =1411410a(20) =1438710a(21) =10010910a(22) =7402395a(23) =28393365a(24) =20930910a(25) =9699690a(26) =23393370a(27) =77087010a(28) =117110994a(29) =324939615