fnA 1.31 could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The actual developer of the software is RJ Software.
The following version: 1.3 is the most frequently downloaded one by the program users. We recommend checking the downloaded files with any free antivirus. The most frequent installation filenames for the software are: Five_nights_at_Hypos.exe and FNA.exe etc. The software relates to Business Tools.
From the developer:
FNA is a multi-function scientific calculator and unit conversion utility. Four modes of operation (statistics, trigonomety, base-n, and unit conversion). Convert units of Acceleration, Angle, Area, Density, Energy, Force, Fuel Efficiency, Length, Mass/Weight, Power, Pressure, Speed, Temperature, Time, Torque and Volume.
You may want to check out more software, such as FNaF-MINECRAFT, FNaF - Bonnie Simulator or AGEman, which might be related to fnA.