MathDB
no of binary sequences of length n that are not equivalent.

Source: 2004 VMEO I p6 Vietnamese Mathematics e - Olympiad https://artofproblemsolving.com/community/c2461015_vmeo__vietnam_mathematical

September 26, 2021
combinatoricsSequences

Problem Statement

Consider all binary sequences of length nn. In a sequence that allows the interchange of positions of an arbitrary set of kk adjacent numbers, (k<nk < n), two sequences are said to be equivalent if they can be transformed from one sequence to another by a finite number of transitions as above. Find the number of sequences that are not equivalent.