Returns the number of neutrons in the most common stable isotope of the first ten elements of the Periodic Table, indicated by atomic number.

The four inputs a₀, a₁, a₂, a₃ indicate the element’s atomic number, with a₀ being the least significant bit, and a₃ the most significant bit.

The five outputs n₀, n₁, n₂, n₃, n₄ indicate the neutron count of the element’s most common stable isotope, as well as any error condition, with n₀ being the least significant bit of the neutron count, n₃ the most significant bit, and n₄ being a flag bit that is 1 in case of an error, 0 otherwise.

Since the smallest atomic number is 1, an input value of 0 will set the error flag to 1. Although the input bits can represent a maximum value of 15₁₀, meaningful output is only guaranteed for the first ten atomic numbers. Input values above 10₁₀ will also set the error flag to 1.