Numbers n such that Sum_{i = 1..q} 1/d(i) is an integer where d(i) are the divisors of n for some q and n is primitive (the set {d(1), d(2), ..., d(q)} appears only once).
A226853
Numbers n such that Sum_{i = 1..q} 1/d(i) is an integer where d(i) are the divisors of n for some q and n is primitive (the set {d(1), d(2), ..., d(q)} appears only once).
Terms
- a(0) =1a(1) =6a(2) =28a(3) =120a(4) =180a(5) =496a(6) =672a(7) =1890a(8) =8128a(9) =8415a(10) =20482a(11) =20496a(12) =25410a(13) =30240a(14) =32760a(15) =33345a(16) =34155a(17) =38430a(18) =40128a(19) =47804a(20) =72800a(21) =90720a(22) =103530a(23) =407715a(24) =523776a(25) =806190a(26) =979992a(27) =1084160a(28) =1273725a(29) =1274100
External references
- oeis: A226853