I thought it was 1024x576
Both of these answers depend somewhat on what pixel ratio you have selected in Photoshop. Very often the pixel dimensions given in response to questions like this assume that you are working with square pixels. If you change the pixel ratio in photoshop to match the sequence pixel ratio, then the dimesnions will be different.
That was before Adobe changed the par.
1024 will give you black bars on the side and you will have to scale it up.
1050 is 'full screen'.