a(n) = Sum_{k=1..n} sigma_{n-k}(k), where sigma_m(k) = Sum_{j|k} j^m.
A108639
a(n) = Sum_{k=1..n} sigma_{n-k}(k), where sigma_m(k) = Sum_{j|k} j^m.
Terms
- a(0) =1a(1) =3a(2) =6a(3) =13a(4) =29a(5) =77a(6) =229a(7) =771a(8) =2863a(9) =11573a(10) =50365a(11) =234161a(12) =1156039a(13) =6031751a(14) =33130187a(15) =190929778a(16) =1151198268a(17) =7243777234a(18) =47462906927a(19) =323188163753
External references
- oeis: A108639