Yes, SEQUENCES is a Scrabble word!

Letter values in Scrabble US: S 1, E 1, Q 10, U 1, E 1, N 1, C 3, E 1, S 1.

Is it a valid word?

SEQUENCES is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

serial arrangement in which things follow in logical order or a recurrent pattern
a following of one thing after another in time
film consisting of a succession of related shots that develop a given subject in a movie
the action of following in order
several repetitions of a melodic phrase in different keys

Also: chronological sequence, chronological succession.