Numbers n such that sigma(n+1) - sigma(n-1) = k*n for some integer k, where sigma(n) = A000203 (sum of divisors of n).
A223137
Numbers n such that sigma(n+1) - sigma(n-1) = k*n for some integer k, where sigma(n) = A000203 (sum of divisors of n).
Terms
- a(0) =5a(1) =34a(2) =55a(3) =285a(4) =367a(5) =835a(6) =849a(7) =919a(8) =1241a(9) =1505a(10) =2911a(11) =2914a(12) =3305a(13) =4149a(14) =4188a(15) =6111a(16) =6903a(17) =7170a(18) =7913a(19) =9360a(20) =10251a(21) =10541a(22) =12566a(23) =15086a(24) =17273a(25) =17815a(26) =19005a(27) =19689a(28) =21411a(29) =21462
External references
- oeis: A223137