31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365
-
The pattern is every month, starting from January going to December. The numbers are the number of days in each month, and each time the pattern goes on, that number is added to the total. Here are the month's days in order from January to December:
31
28
31
30
31
30
31
31
30
31
30
31
31
28
31
30
31
30
31
31
30
31
30
31
-
28, 31, 30, 31, 30, 31,
-
+31 +30 +31 +30