The smaller of a pair of successive powerful numbers without a nonsquarefree number between them.

Terms

a(0) =1a(1) =4a(2) =8a(3) =25a(4) =32a(5) =288a(6) =675a(7) =968a(8) =1152a(9) =1369a(10) =2700a(11) =9800a(12) =12167a(13) =39200a(14) =48668a(15) =70225a(16) =235224a(17) =332928a(18) =465124a(19) =1331712a(20) =1825200a(21) =5724500a(22) =7300800a(23) =11309768a(24) =78960996a(25) =189750625a(26) =263672644a(27) =384199200a(28) =592192224a(29) =912670088