Numbers k such that the average of squarefree kernels of all positive integers <= k is an integer.

Terms

a(0) =1a(1) =3a(2) =4a(3) =17a(4) =53a(5) =433a(6) =456a(7) =901a(8) =1052a(9) =4011a(10) =14504a(11) =15111a(12) =156408a(13) =245423a(14) =328408a(15) =911340a(16) =2263141a(17) =13736475a(18) =20092485a(19) =37903271a(20) =60003559a(21) =78733423a(22) =84206981a(23) =234095587a(24) =319691535a(25) =986119609a(26) =1488787296a(27) =6139123252a(28) =8663152552a(29) =11909530004