a(n) = (n!/6) * Sum_{i,j,k > 0 and i+j+k=n} d(i)*d(j)*d(k)/(i*j*k), where d(n) is the number of divisors of n.
A338811
a(n) = (n!/6) * Sum_{i,j,k > 0 and i+j+k=n} d(i)*d(j)*d(k)/(i*j*k), where d(n) is the number of divisors of n.
Terms
- a(0) =0a(1) =0a(2) =1a(3) =12a(4) =100a(5) =870a(6) =7588a(7) =73808a(8) =764524a(9) =8448120a(10) =103816944a(11) =1334764728a(12) =18483356736a(13) =274780501632
External references
- oeis: A338811