Numbers k such that Sum_{d|k} tau(d)/d is an integer, where tau(x) = A000005(x).

Terms

a(0) =1a(1) =2a(2) =9a(3) =18a(4) =105a(5) =210a(6) =24375a(7) =48750a(8) =133848a(9) =18780741a(10) =18780965a(11) =37561482a(12) =37561930a(13) =121486365a(14) =169028685a(15) =242972730a(16) =338057370a(17) =360988056a(18) =676114740a(19) =1120584213a(20) =1285201500a(21) =1352229480a(22) =2241168426a(23) =2776831200a(24) =5352575025a(25) =5408917920a(26) =7437262140a(27) =10705150050