Pattern Recognition - 121

Find out the next two numbers in the series.
255 , 321 , 353 , 417 , _ ,_ ,..................


Answer

255 ,     321 ,     353 ,      417 , _ ,_ ,..................
      +66      +32        +64

55 +11 =66
21 +11 =32
53 +11 =64

Next two numbers   17 +11 =28      417 + 28 = 445
                            45 +11 =56      445 + 56 = 501

255 , 321 , 353 , 417 , 445 ,501 ,..................