Formulating the words of the Omer count

...with regard to the question of whether we use the formulation "בעומר" or "לעומר", there is no definitive decision. My preference is for "לעומר", and indeed this is our tradition...

...if a person counted using an abbreviation; for example, they used the formula היום ג’ ימים בעומר, there is a difference of opinion as to whether they fulfilled their obligation. It seems to me that this is no worse than counting in a language other than Hebrew. At the most they should count again without a blessing...

...and as to the question of someone who wrote out the count in words, have they fulfilled their obligation? We can answer this question by looking at whether or not they had intention to fulfil.

(a) If they did not have intention, then one could argue that even from the perspective that one does not need intention to fulfil a mitzvah, their count does not count, the reason being that they did not perform the mitzvah in the correct way so this is as if they had explicit intention not to fulfil the obligation.

(b) Even if they did have intention, it would appear that they did not fulfil the mitzvah. There is a principle that כתיבה כדיבור דמי, by writing something it is as if you said it, but that only applies when you are writing in order to express a thought or emotion, but this principle does not apply to the performance of a mitzvah. An analogy can be made to someone who writes out the text of the Shema or the Amidah. Certainly such a person has not fulfilled their obligation to pray. Likewise someone who writes out the text of ברכת המזון.