Stable recursive relations are presented for the numerical computation of the
integrals
∫dr1dr2r1l−1r2m−1r12n−1exp{−αr1−βr2−γr12}
(l, m and n integer, α, β and γ real) when the
indices l, m or n are negative. Useful formulas are given for particular
values of the parameters α, β and γ.Comment: 12 pages, 1 figure (PS) and 3 tables. Old figures 2 and 3 replaced by
Tables I and III. A further table added. Paper enlarged giving some tips on
the convergence of quadrature