M B ( $^{3}$H) B ( $^{3}$He) $^{2}$a$_{nd}$ $^{4}$a$_{nd}$ $^{2}$a$_{pd}$ $^{4}$a$_{pd}$ 4 -8.5117 -7.8404 1.0207 6.4590 0.3987 14.088 8 -8.5351 -7.8683 0.7251 6.4434 0.0363 13.978 12 -8.5357 -7.8688 0.7031 6.4413 0.00636 13.967 16 -8.5357 -7.8689 0.7019 6.4412 0.00472 13.966 20 -8.5357 -7.8689 0.7018 6.4412 0.00461 13.965 24 -8.5357 -7.8689 0.7018 6.4412 0.00458 13.965 28 -8.5357 -7.8689 0.7018 6.4412 0.00456 13.965 32 -8.5357 -7.8689 0.7018 6.4412 0.00454 13.965 TABLE II: Convergence of the $^{3}$H and $^{3}$He bound states (in MeV) and the n − d and p − d doublet and quartet scattering lengths (in fm), using the PHH expansion, as a function of the number of Laguerre polynomials M . 26