Amino acid substitutions near the receptor binding site HA protein in type A H3N2 influenza strains?
Short answer: Yes, 156 is generally considered "near" the RBS, e.g. in this paper you can see it mapped onto the structure.  

For a more general answer, you'll need to sit down and stare at 3D models of hemagglutinins (there are hundreds in the PDB), just like the rest of us. Antibody binding sites are not black and white, and interactions between influenza and antibodies are wildly complicated. What's "near" in some contexts might be "far" in others. 

You might find the Influenza Research Database's Identify Sequence Features in Segments tool useful, particularly its annotation of hemagglutinin H3. 

Be aware that numbering of amino acids can be confusing, since different groups may be using different starting points. There's a vague agreement on the "correct" numbering, but quite a few groups pay it lip service and then number their version however they like.