Is it ensure, insure, or assure?
1550s, "following," from Old French sequent "following, subsequent," from Latin sequentem (nominative sequens) "next, following," present participle of sequi "to follow" (see sequel). As a noun from 1580s.
A computer manufacturer.
Quarterly sales $109M, profits $7M (Aug 1994).
Sequent computers was acquired by IBM in 1999.