"Such-and-such (a)" + singular noun

I've found both versions, She lives in such-and-such a street AND She lives in such-and-such street

Are both uses of the determiner? Which is the right one?

OED entry for such

This is interesting, and there does seem to be divided usage. Google ngrams for such and such a street and such and such street (and a check on references given at the link) show that both are used (with various choices of hyphenation), the one containing the article 'a' being five times as common a choice.

This is probably because there is an attempt to conform to standard grammar, though logically 'such and such a' is no better than 'such and such' as a placeholder some would portray as _____ or XXXX.

Collins Cobuild does not analyse such and such more than to call the whole a phrase; when used before a noun, the near-equivalence of 'some' might make some argue for determiner classification. And Collins does not even comment on the fact that a is typically included before a noun. As seen below, the distribution of 'such and such [a]' is fairly wide, not merely prenominal:

such and such [phrase]:

You use such and such to refer to a thing or person when you do not want to be exact or precise. [spoken, vagueness]

• I said, 'Well what time'll I get to Leeds?' and he said such and such a time but I missed my connection.
• He'd like to give a course of lectures on such and such a topic.
• we went to such and such a place [from Webster's]
• Or that the friend you trusted was going to betray you in some way on such and such a date? [Anthony Masters: Cascades - The Day of the Dead]
• And so we produce masses of documented research to define a target audience in such and such a demographic. [Stuart Harrison: Better than This]

The last example is more unusual, as 'such and such [a]' is, as Collins adds, usually used in informal contexts.

[re-ordered]

Collins includes examples where 'such and such' is not used before a noun, and the 'a' is inappropriate:

• What if such and such had happened instead? [used ostensibly as a noun phrase]
• Father, forgive me for I have sinned, she said, my last confession was such and such ago. [Louise Erdrich: The Last Report on ...] [used ostensibly as a measure phrase]