Listing archivelog that are backed up 2 times by RMAN

1.Listing archivelog that are backed twice to device type disk

RMAN> list archivelog all backed up 2 times to device type disk;

List of Archived Log Copies for database with db_unique_name CVRMAN
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Key     Thrd Seq     S Low Time
------- ---- ------- - --------------------
47      1    12      A 15-MAY-2014 07:42:19
        Name: +DATA/cvrman/archivelog/2014_05_15/thread_1_seq_12.319.847663387