Call a sequence a1 a2 an of positive integers a restricted

Call a sequence a_1, a_2, ..., a_n of positive integers a restricted growth sequence if a_1 = 1 and for each i > 0 a_i lessthanorequalto max_j

Solution

A restricted growth function (RGF) is a sequence A = a₁a₂a₃ . . . a_n.

Number of elements of A is called the the length of A and represented as l(A).

For example A = 1221334 is a RGF whith l(A) = 7

A = 1231346 is not a RGF because there is no number 5 before 6.