Calculate Third Wednesday Of Month Plus Interval

For any given year, I would like to calculate the date of the third Wednesday of each month for that year, plus the interval (in weeks) between two consecutive months (Which will be either 4 or 5).

Example:
Enter 2013 in cell A1
Output would be:
A2 - Jan 16
A3 - Feb 20
A4 - Mar 20
A5 - Apr 17
..
A13 - Dec 18

AND

B3 - 5 weeks (interval Jan-Feb)
B4 - 4 weeks (interval Feb-Mar)
B5 - 4 weeks (interval Mar-Apr)
..
B13 - 4 weeks (interval Nov-Dec)