a(n) = denominator of Sum_{1 <= i < j <= d(n)} 1/(d_j - d_i), sum over ordered pairs of divisors of n, where d(n) is the number of divisors of n.
A330078
a(n) = denominator of Sum_{1 <= i < j <= d(n)} 1/(d_j - d_i), sum over ordered pairs of divisors of n, where d(n) is the number of divisors of n.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =4a(5) =60a(6) =6a(7) =28a(8) =24a(9) =360a(10) =10a(11) =3960a(12) =12a(13) =1820a(14) =105a(15) =280a(16) =16a(17) =85680a(18) =18a(19) =4560a(20) =630a(21) =13860a(22) =22a(23) =425040a(24) =120a(25) =28600a(26) =234a(27) =98280a(28) =28a(29) =254475
External references
- oeis: A330078