Is this a Major Scale (or equivalent)?
Perl 6, 76 65 63 59 bytes

-4 bytes thanks to Phil H



{221222==[~] (.skip Z-$_)X%12}o*&gt;&gt;.&amp;{13*.ord+&gt;3+?/\#/-?/b/}


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Explanation

*&gt;&gt;.&amp;{ ... }  # Map notes to integers
  13*.ord     # 13 * ASCII code:  A=845 B=858 C=871 D=884 E=897 F=910 G=923
  +&gt;3         # Right shift by 3: A=105 B=107 C=108 D=110 E=112 F=113 G=115
              # Subtracting 105 would yield A=0 B=2 C=3 D=5 E=7 F=8 G=10
              # but isn't necessary because we only need differences
  +?/\#/      # Add 1 for '#'
  -?/b/       # Subtract 1 for 'b'

{                           }o  # Compose with block
            (.skip Z-$_)        # Pairwise difference
                        X%12    # modulo 12
         [~]  # Join
 221222==     # Equals 221222