Is this the Fourier Number, or some other formula?

[nomadreid]

This is on a building in Korea, and the F₀ made me think of the Fourier number, but the rest of the formula is unfamiliar to me. Does anyone recognize it?

 

[Baluncore]

It looks like the fundamental frequency of a vibrating string or rod.

 

[Baluncore]

It might be the fundamental frequency of the brick wall, a private joke between the architects and engineers, since earthquakes are possible and the "writing is on the wall".