L.g.f.: exp(Sum_{n>=1} a(n)*x^n/n) = 1 + x*exp(Sum_{n>=1} sigma(n)*a(n)*x^n/n).
A158108
L.g.f.: exp(Sum_{n>=1} a(n)*x^n/n) = 1 + x*exp(Sum_{n>=1} sigma(n)*a(n)*x^n/n).
Terms
- a(0) =1a(1) =1a(2) =4a(3) =21a(4) =186a(5) =1366a(6) =19433a(7) =180541a(8) =3083809a(9) =44941136a(10) =895695901a(11) =11809732422a(12) =359749783368
External references
- oeis: A158108