# Microsoft SQL Server, 57 Bytes
    
    SELECT UPPER(FORMAT(CAST('201601'+'01' AS DATE),'MMMyy'))

The `Upper` function is required as format does not produce Upper case months as would be expected with the *MMM* format pattern.

   **Usage:**
    
    drop table t;
    create table t (n VARCHAR(6));
    insert into t values ('201604');
    insert into t values ('200001');
    insert into t values ('000112');
    insert into t values ('123405');    

    SELECT UPPER(FORMAT(CAST(n+'01' AS DATE),'MMMyy')) FROM t