Numbers k such that Sum_{d|k} sigma(d)/d is an integer.

Terms

a(0) =1a(1) =21a(2) =105a(3) =1050a(4) =1155a(5) =24921a(6) =26565a(7) =45150a(8) =49842a(9) =59455a(10) =249210a(11) =274131a(12) =548262a(13) =1129645a(14) =1151325a(15) =1248555a(16) =1309350a(17) =2302650a(18) =2741310a(19) =3388935a(20) =4605300a(21) =6305013a(22) =12610026a(23) =13417131a(24) =14685385a(25) =23722545a(26) =25750550a(27) =26834262a(28) =30154410a(29) =33388425