OFFSET
1,3
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..1000
FORMULA
Equals the logarithmic derivative of A192860.
EXAMPLE
L.g.f.: L(x) = = x + x^2/2 + 7*x^3/3 + 9*x^4/4 + 26*x^5/5 + 37*x^6/6 +...
which is generated by:
L(x) = x + (x + 2*x^2)^2/2 + (x + 3*x^3)^3/3 + (x + 2*x^2 + 4*x^4)^4/4 + (x + 5*x^5)^5/5 + (x + 2*x^2 + 3*x^3 + 6*x^6)^6/6 + (x + 7*x^7)^7/7 + (x + 2*x^2 + 4*x^4 + 8*x^8)^8/8 +...
Exponentiation of the l.g.f. yields the g.f. of A192860:
exp(L(x)) = 1 + x + x^2 + 3*x^3 + 5*x^4 + 10*x^5 + 18*x^6 + 45*x^7 +...
MATHEMATICA
With[{m = 30}, Rest[CoefficientList[Series[Sum[(Sum[d*x^d, {d, Divisors[n] }])^n/n, {n, 1, m + 2}], {x, 0, m}], x]]*Range[1, m]] (* G. C. Greubel, Jan 07 2019 *)
PROG
(PARI) {a(n)=local(A=x); A=sum(m=1, n+1, sumdiv(m, d, d*x^d +x*O(x^n))^m/m); n*polcoeff(A, n)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jul 11 2011
STATUS
approved