The Legendre-Stirling numbers are the specialization at of the Jacobi-Stirling
numbers. The numbers of the second kind satisfy
while the numbers of the first kind satisfy
Both use the boundary values and zero when exactly one index is zero. They
are connection coefficients for polynomial bases associated with the Legendre differential operator, whose polynomial eigenfunctions
are the Legendre polynomials.
Andrews, G. E.; Egge, E. S.; Gawronski, W.; and Littlejohn, L. L. "The Jacobi-Stirling Numbers." J. Combin. Theory
Ser. A120, 288-303, 2013. https://doi.org/10.1016/j.jcta.2012.08.006.