Information on mass chains and nuclides available on this website:

WWW TUNL

¹³Be is not observed in the 5.5 GeV proton bombardment of uranium (PO68B) nor in the bombardment of ²³²Th by 145 MeV ¹⁵N ions (AR70H). ¹³Be is predicted to have an atomic mass excess of 35.35 MeV. It is then unstable with respect to decay into ¹²Be + n by 2.32 MeV (TH74). The modified mass equation leads to an amu of 34.60 MeV; ¹³Be would then be unstable with respect to decay into ¹²Be + n by 1.50 MeV (JE75). See also (TH72K, BA73L, KO73F, VO73M, BE75Q).