Re: 5515-Year Luni-Solar Cycle

A 39-week solar calendar can be devised such that

5515 weeks = 1749 months = 141 & 16 / 39 years

Each three weeks would group into 13th-of-year months ( A, B, C, ... )
In its symmetrical form...
---------
A  9, 10, 9
B  9, 10, 9
---------
C 10, 9, 9
D 10, 9, 9
E 10, 9, 9
F 10, 9, 9
---------
G 10, 9, 10
---------
H  9, 9, 10
I  9, 9, 10
J  9, 9, 10
K  9, 9, 10
---------
L  9, 10, 9
M  9, 10, 9
---------
Almost every solar month contains a new moon. Except that in 5515 years, there are 3484 orphan months, or drifts over the solar month.
There are 2031 years in which every solar month contains a new moon. This coincides with the 2031 13-month years on the luni-solar calendar.