L.g.f.: Sum_{n>=1} a(n)*x^n/n = Sum_{n>=1} (1 + sigma(n)*x)^n * x^n/n.
A159309
L.g.f.: Sum_{n>=1} a(n)*x^n/n = Sum_{n>=1} (1 + sigma(n)*x)^n * x^n/n.
Terms
- a(0) =1a(1) =3a(2) =10a(3) =35a(4) =116a(5) =606a(6) =2990a(7) =11203a(8) =65368a(9) =567558a(10) =3229942a(11) =12730946a(12) =78628616a(13) =666394746a(14) =3968286590a(15) =21143707843a(16) =160244432497
External references
- oeis: A159309