Frobenius number

Etymology
After Ferdinand Georg Frobenius.

Noun

 * 1) For a given set of coprime positive integers, the greatest integer that cannot be expressed as a linear combination (with nonnegative integer coefficients) of its elements.
 * The Frobenius number of 2 and 5 is 3, since 3 cannot be formed as a sum of twos and fives while every larger integer can.