Name of dsRNA (or dsDNA) where all strands are identical
Such a nucleic acid sequence is described as a palindrome or palindromic.

Wikipedia has an entry for palindromic sequence in which it is defined as:


  A palindromic sequence is a nucleic acid sequence on double-stranded DNA or RNA wherein reading 5′ (five-prime) to 3′ (three prime) forward on one strand matches the sequence reading 5′ to 3′ on the complementary strand with which it forms a double helix. This definition of palindrome thus depends on complementary strands being palindromic of each other.


It should be noted that this is a description (rather than a name) that is usually applied to segments of larger nucleic acid molecules or to synthetic constructs. I am not aware of a generic name for short dsRNA (or dsDNA) like the one in the question as they are not, to my knowledge, found in Nature and so there has been no reason to devise a name for them. Thus, there are no names for variants either. If you wish to write an article about such things you would need to invent your own terms, but keep well clear of ‘-mers’ (see use of e.g. tetramer).

The sequence presented in the question does not conform to the Wikipedia definition, above, as it has a central mismatch and is therefore not a perfect double-helix. However, as the use of the term palindrome for nucleic acids is a somewhat cavalier extension of the general use of the English word palindrome (an example of which is “ABLE WAS I ERE I SAW ELBA”), I would regard a further minor modification of the Wikipedia author’s definition as unexceptionable.