Binding-Energy Systematics of 0$^{+}$, 2$^{+}$, 3$^{-}$, and 4$^{-}$, T=0 States of Even-Even Self-Conjugate Nuclides from $^{16}$O to $^{40}$Ca

Binding energies of self-conjugate even-even nuclides are plotted as --\textit{B}$^{*}$+(9.5 MeV)$^ {.}$ \textit{A}\textrm{ versus mass number } \textit{A}, \textrm{ where }\textit{B}$^{*} $ is the binding energy of ground states and levels. A diagram from \textit{A}=0 to 76 mainly for ground states shows a subshell systematics. In a diagram from \textit{A} =16 to 40, established and hypothetical 0$^{+}$ levels are shown; 24 states of supposed 1d$_{5/2}$, 2s$_{1/2}$, and 1d$_ {3/2}$ subshell occupations are connected by almost linear trends. Surprisingly, early insufficient measurements at E$_{x} =0.65$ MeV in $^{20}$Ne and 0.5 (and 0.43) MeV in $^{32}$S fit the trends. A diagram for the 0$^{+}$, 2$^{+}$, 4$^{+}$, and 6$^ {+}$ band from $^{16}$O to $^{28}$Si suggests the 0$^{+}$ head in $^{20}$Ne to be at 0.65 MeV. A systematics of 2$^{+}$ states supports both levels. A plot of 3$^{-}$ and 4$^{-}$ states contains two pairs of nearly parallel and linear 3-point trends. Two odd 2s$_{1/2}$ and 1f$_ {7/2}$ nucleons couple to 3$^{-}$ and (not completely established) to 4$^{-}$ in trends $\approx$1.6 and $\approx$1.7 MeV above. Below each of the two pairs of trends, the 0$^{+}$ trends are expected to be also nearly linear, which they are with these complementary $^{20}$Ne and $^{32}$S levels. A table suggests a total of 18 important experimental investigations.