a(n) = index where A088568 (or equally A294448) first reaches or exceeds n in magnitude.

Terms

a(0) =1a(1) =12a(2) =93a(3) =378a(4) =471a(5) =858a(6) =1127a(7) =1398a(8) =1497a(9) =1524a(10) =1533a(11) =20338a(12) =20371a(13) =21982a(14) =22009a(15) =25638a(16) =25665a(17) =25692a(18) =27969a(19) =39184a(20) =39211a(21) =42398a(22) =43129a(23) =43150a(24) =48637a(25) =48730a(26) =48757a(27) =49014a(28) =49041a(29) =49068