The phrase "a frequent one" is correct and usable in written English.
It can be used to describe something that occurs often or is common in a particular context.
Example: "This type of error is a frequent one in our reports, and we need to address it."
Alternatives: "a common occurrence" or "a regular issue".
In "Parsifal" it is a disaster, and a frequent one.
The problem is not a frequent one, she said, but it does happen, because the majestic ceiling has no escape hole that flying creatures could use.
Prone to folksy sayings that charm the slick Hollywood crowd — "your cheese done slid off your cracker" is a frequent one and means "you're out of your mind" — Mr. Pons grew up in the rural North Carolina hills, where his parents run the Christian Training Center International.
The line of attack is a frequent one, attracting millions of dollars in spending from the Democratic Senatorial Campaign Committee.
A frequent one is, "How will kids learn to do things they don't like if they are not made to do them?" You would think that formal education would aim a little higher than teaching children how to endure.
A frequent one is "nightmare". The Culkins--whose combination of Macaulay's celebrity and Kit's notoriety have ensured a high media profile--are back in the news because they are coming apart.
From the second game of the season, which he won in Anaheim with a two-run home run in the ninth inning, Williams has staged a frequent one-man victory party.
Comet 67P/Churyumov-Gerasimenko was selected to be Rosetta's target because its path round the Sun is a regular, frequent one.
The clause in question is a very frequent one in public service contracts; it should be possible to resort to its use even if this leads to the contract lasting longer than the otherwise applicable limit.
It is, however, an increasingly frequent one".
Genetic diversity was low, with only four haplotypes: a central, most frequent, one surrounded by two haplotypes differing by an indel and one differing by a substitution.
