However, BDAG says271. The indefinite relative is ὅστις, ἥτις, ὅ τι, whoever, whatever. It is compounded from ὅς and τις, both of which are declined. It appears, however, only in the following forms:
Singular
M F N
N ὅστις ἥτις ὅ τι
A ὅ τι
Plural
M F N
N οἵτινες αἵτινες ἅτινα
2710. Notes:
Should Funk have listed the genitive?ὅτου gen. sing. masc. and neut. of ὅστις (q.v. 6).
I also note that almost all occurrences of ὅστις are in the nominative case, except for the accusative neuter and frozen forms like ἕως ὅτου, πρὶν ὅτου (rare), μέχρι ὅτου. What's up with that?