Information on mass chains and nuclides available on this website:

WWW TUNL

¹⁵Li has not been observed: its atomic mass excess is calculated to be 81.60 MeV. It is then unstable with respect to decay into ¹⁴Li + n and ¹³Li + 2n by 1.24 and 3.90 MeV, respectively (TH74).