OFFSET
1,2
COMMENTS
Logarithmic derivative of A185301.
FORMULA
L.g.f.: Sum_{n>=1} Sum_{k>=1} sigma(n)^k * x^(n*k)/n = Sum_{n>=1} a(n)*x^n/n.
EXAMPLE
L.g.f.: L(x) = x + 5*x^2/2 + 7*x^3/3 + 29*x^4/4 + 11*x^5/5 + 131*x^6/6 + ... where exp(L(x)) = 1 + x + 3*x^2 + 5*x^3 + 14*x^4 + 20*x^5 + 59*x^6 + 83*x^7 + 229*x^8 + 350*x^9 + 878*x^10 + ... + A185301(n)*x^n + ...
MATHEMATICA
a[n_] := DivisorSum[n, # * DivisorSigma[1, n/#]^# &]; Array[a, 40] (* Amiram Eldar, Aug 18 2023 *)
PROG
(PARI) {a(n)=sumdiv(n, d, d*sigma(n/d)^d)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jan 25 2012
STATUS
approved