Is mentioning and repeating Allah's name as a means of dhikr, like saying ‘Allah Allah Allah’ correct?

The noble ayahs and authentic ahadith reported from the Prophet (ﷺ) indicated that the best of speech is the word of Tawhid: La ilaha illa Allah (there is no god but Allah), according to his saying:

“There are more than seventy branches of Iman (Faith/belief), the most superior of which is saying "La Ilaha Illa Allah" He (peace be upon him) had also said: “The most preferred words to Allah are four: Subhan Allah (Glorified be Allah), Al-Hamdulillah (Praise be to Allah), la ilaha illa Allah (There is no god but Allah) and Allahu Akbar (Allah is the Greatest).”[1]

Moreover, Allah has mentioned this word in the Qur'an in many places, among which is His saying:

“Allâh bears witness that Lâ ilâha illa Huwa (none has the right to be worshipped but He)” [2]

“So know (O Muhammad (ﷺ)) that, Lâ ilâha illallâh (none has the right to be worshipped but Allâh), and ask forgiveness for your sin.”[3]

Thus, it is prescribed for Muslims to remember Allah using this word: La Ilaha Illa Allah in addition to other good permissible words such as Subhan Allah, Al-hamdullilah, Allahu Akbar and La hawla wala Quwwata Illa Billah (There is neither strength nor power except with Allah).

As for the Sufis' saying: words like "Allah, Allah" or "He, He", this is verily an act of bid`ah (innovation in religion) and people should not adhere to this, for it had not been reported from the Prophet (ﷺ) or any of his Companion.[4]

Thus, repeating the name of Allah only, is as meaningless as one saying “Taariq, Taariq, Taariq” which neither praises Allah nor asks Allah for anything. Moreover, it is from Hindu traditions that they keep on repeating "OM, OM”.

References: 

[1] Sahih Muslim, Book 16, Hadith 1589

[2] Surah ‘Ale-Imran, 3:18

[3] Surah Muhammed, 47:19

[4] Fatwas of Ibn Baz: Volume 8: Method of pronouncing Dhikr according to the Sufi order