I'm going to disagree here a little bit. I'm not going to offer an in-depth analysis of the Beethoven because I will present my answer in general terms.
While Wikipedia's definition of a sequence asserts that it is the "immediate restatement of a motif or longer melodic (or harmonic) passage at a higher or lower pitch in the same voice[,]" this definition is incomplete and not necessarily correct.
A sequence can be in any number of voices. Sequences can happen simultaneously, and they do not have to be part of the melody. You could have an accompaniment that is a sequence.
Essentially, a sequence is a motivic element that repeats. This motive does not have to be related to the melody, or even the accompaniment for that matter. When stripped down, the only difference between a sequence and an ostinato is motion.
Where ostinati are typically static, sequences are usually rising or falling, jumping, or thickening (here the term "stretto" can be applied.)
To answer your question, yes, a sequence can be rhythmically modified. The two terms for this are augmentation and diminution. Augmentation is as it suggests - stretching or lengthening things out. Diminution can then be reasoned to be a shortening of things.
Sequences can be stretched in terms of durational length, iterations of motive, or changes in orchestration to name a few, and they can be diminished in exactly the same ways as well.
That said, what you have pointed out in the excerpt in question is not a sequence. It is not a motive. It is really nothing more than rhythmic augmentation of a transposition creating a half-cadence between antecedent and consequent phrases.
This is a wonderful movement of a wonderful piece of music, but I don't think it is the most representative of a piece with abundant sequences. Again, I will defer to J.S. Bach, the Sequence King.