This is what I have for controlling tabs:

    " Mappings for controlling tabs.
    noremap <M-a> :tabprevious<CR>
    noremap <M-s> :tabnext<CR>
    noremap <M-1> :tabnext 1<CR>
    noremap <M-2> :tabnext 2<CR>
    noremap <M-3> :tabnext 3<CR>
    noremap <M-4> :tabnext 4<CR>
    noremap <M-5> :tabnext 5<CR>
    noremap <M-6> :tabnext 6<CR>
    noremap <M-7> :tabnext 7<CR>
    noremap <M-8> :tabnext 8<CR>
    noremap <M-9> :tabnext 9<CR>

More here: https://github.com/daGrevis/Dotfiles/blob/master/.vimrc .