OFFSET
1,1
EXAMPLE
L.g.f.: L(x) = 2*x + 34*x^2/2 + 1538*x^3/3 + 262178*x^4/4 + ...
exp(L(x)) = 1 + 2*x + 19*x^2 + 548*x^3 + 66749*x^4 + ... (A158099).
MATHEMATICA
a[n_] := DivisorSum[n, # * 2^(#^2) &]; Array[a, 10] (* Amiram Eldar, Aug 18 2023 *)
PROG
(PARI) a(n)=sumdiv(n, d, d*2^(d^2))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Dec 16 2009
EXTENSIONS
a(11)-a(12) from Amiram Eldar, Aug 18 2023
STATUS
approved