The Ramanujan-Nagell Theorem states that the equation two to the power n minus seven equals x squared has exactly five solutions in positive whole numbers, with n equal to 3, 4, 5, 7 or 15. First conjectured by Srinivasa Ramanujan and proved by Trygve Nagell, it is a classical result in the theory of exponential Diophantine equations and an early example of such an equation whose complete, finite set of solutions could be established rigorously.
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Entity-backed identity for the statement-form enum value this theorem already carries, resolved to a mathematics concept by an explicit value-to-entity map (phase 3 bucket conversion, docs\design_entity_backed_browse_buckets_20260928.md). The statement-form fact itself stays on the theorem unchanged.
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Source Ramanujan-Nagell equation (Wikipedia)
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1. Ramanujan-Nagell equation (Wikipedia)
Equation and solution sectionQuote, Equation and solution section
proved in 1948 by the Norwegian mathematician Trygve Nagell
Ramanujan-Nagell equation (Wikipedia)
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