a(n) = denominator of Sum_{d|n} (tau(d)/sigma(d)) where tau(k) = the number of the divisors of k (A000005) and sigma(k) = the sum of the divisors of k (A000203).
A323780
a(n) = denominator of Sum_{d|n} (tau(d)/sigma(d)) where tau(k) = the number of the divisors of k (A000005) and sigma(k) = the sum of the divisors of k (A000203).
Terms
- a(0) =1a(1) =3a(2) =2a(3) =21a(4) =3a(5) =2a(6) =4a(7) =105a(8) =26a(9) =9a(10) =6a(11) =7a(12) =7a(13) =12a(14) =1a(15) =3255a(16) =9a(17) =26a(18) =10a(19) =63a(20) =8a(21) =18a(22) =12a(23) =35a(24) =93a(25) =21a(26) =65a(27) =21a(28) =15a(29) =3
External references
- oeis: A323780