login
a(n) = n! * Sum_{k=1..n} ( Sum_{d|k} d^(k/d + 1) )/(k * (n-k)!).
1

%I #13 Aug 15 2022 08:41:15

%S 1,7,38,264,1629,16075,122366,1414952,16076913,213998983,2112313774,

%T 53581378400,664573162941,9967808211387,239545427723062,

%U 5933102008956848,79857813309308609,2677379355344673255,44453311791217697686,1743982053518367438616

%N a(n) = n! * Sum_{k=1..n} ( Sum_{d|k} d^(k/d + 1) )/(k * (n-k)!).

%F a(n) = n! * Sum_{k=1..n} A078308(k)/(k * (n-k)!).

%F E.g.f.: -exp(x) * Sum_{k>0} log(1-k*x^k).

%o (PARI) a(n) = n!*sum(k=1, n, sumdiv(k, d, d^(k/d+1))/(k*(n-k)!));

%o (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(-exp(x)*sum(k=1, N, log(1-k*x^k))))

%Y Cf. A078308, A353992, A354848, A356598.

%K nonn

%O 1,2

%A _Seiichi Manyama_, Aug 15 2022