The Frobenius number of a set of coprime integers is the largest number that not can be written as the sum of integer multiples of numbers in that set.
I'm looking for a general reference on Frobenius numbers.
There's a book by Jorge L. Ramírez Alfonsín called The Diophantine Frobenius Problem.
J.C.Rosales, P.A.García-Sánchez. Numerical Semigroups. Springer, 2009.
J.Amos, I.Pascu, V.Ponomarenko, E.Trevino, Y.Zhang. The Multi-Dimensional Frobenius Problem. Involve, 4(2) 2011, pp.187-197.