The names of G-d-

We are not allowed to say the name of G-d in vain, The Ashkenazim hold with the Ro"sh, and say that it is a Rabbinical sin, rather than a Torah sin according to the Sephardim who follow the Ramba"m, and Maran. If one says the words-Baruch Ata A-d-o-n-a-i , and has nothing to say a Bracha on, he should say Lamdeni Hukecha. Since Baruch Ata A-d-o-n-a-i Lamdeni Hukecha is a passuk from Tehilim, it acceptable to say it. That is why in S'firat HaOmer Ashkenazim say the bracha over again, if they said the wrong day, while the Sephardim listen in with another person, and say Amen. The main names of G-d are- A-d-o-n-a-i. E-l-o-h-i-m. Shalom. Sh-a-d-a-i. We call "Hashem", meaning "The Name". If one says the name of Hashem in vain, he must recite this verse- Baruch Shem Kevode Maluchuto LeOlan Va'ed.