Project Euler #128: Hexagonal tile differences

  • + 2 comments

    What is the Logic behind the problem ?

    I can deduce it that the rings are formed in multiple of 6...so

    2 8 20 38 62 92 128 170 218 272.... and these should be the numbers but from this my 10th tile is 272 and not 271.....

    Can anyone help in this ?