S U R F
C A L M
E X P O
T I N Y

Each of the above letters represents a positive integer smaller than 200. In some order they represent an arithmetic sequence. Overall, the grid as presented is a magic square, with each row, each column and each of the two large diagonals adding to the same value.

Also, each of the letters in P-R-I-M-E-S represents a prime number, and in themselves they also form an ascending arithmetic sequence, in the order P-R-I-M-E-S.

What is this magic square?

Also, each of the letters in P-R-I-M-E-S represents a prime number, and in themselves they also form an ascending arithmetic sequence, in the order P-R-I-M-E-S.

2 3 5 7 11 13  How did you envisage getting 5 members of arithmetic progresion out othese 7 numbers  ?