for Ln = La, Ce, Pr and Gd, while the one with n = 3 was not detected beyond La, while analogous compounds with n = 6 were previously not observed in any related series. There are two triangular assemblies per unit cell with the cationic and the anionic components alternating along all crystallographic axes. For instance, the Gd compound with n = 4 is the least disordered approaching an average case observed for the related pnictides. The unique feature of the entire series is though the presence of a mixed Ln/Si site in all compounds in a nearly 1:1 ratio. Such mixing is from the first look unreasonable but is well in line with the most efficient space filling combined with the least possible triangular assemblies distortion. also be noted that the identical anomaly is also not observed for the La-richer series La(n+1)(n+2)Nin(n-1)+2Sin(n+1).