倒數多重階乘常數

m(n)

=

sum_(n=0)^(infty)1/(n!...!_()_(k))

=

1+(e^(1/n))/nsum_(k=1)^(n)n^(k/n)gamma(k/n,1/n)

=

(e^(1/n))/n[n+sum_(k=1)^(n-1)n^(k/n)gamma(k/n,1/n)],

gamma(a,x)

m(2)

=

sqrt(e)[1+sqrt(pi/2)erf(1/2sqrt(2))]

m(3)

=

1/3e^(1/3)[3+3^(1/3)gamma(1/3,1/3)+3^(2/3)gamma(2/3,1/3)].