We provide the definitive answer to the origin of the exact polynomial n (k) = (103k⁴ − 370k³ + 101k² + 478k) /12. The polynomial is the dimension of an irreducible representation of the exceptional Lie group F₄ with highest weight proportional to k: n (k) = dim VF₄ (k·ω₄), where ω₄ is the minimal fundamental representation of dimension 26. The formula is verified analytically (Weyl formula for 24 positive roots) and numerically (LiE, GAP) for k = 1, …, 10. The result explains all previously established connections: the Deligne series, the 691 congruence, linear representations via modular forms, and the SU (26) hierarchy. This is the final paper in a series of six works on the polynomial n (k). Languages: Russian, English. License: UAL v1. 0.
Sergey Viktorovich Matershov (Sat,) studied this question.