Here for the six yerm calendar cycles 17 to 22 inclusive (19 Dec 1721 to 8 Dec 2132), I list pairs of new yerms that occur on the same date in the Gregorian calendar.
The pairs of dates usually occur in a sequence that are 3 yerms of 4 years less 14 days apart. Hence I display the dominical letter of each date after the date. This usually remains unchanged in such a sequence.
Three distinct intervals occur of 144 years, 201 years and 247 years between new yerms on the same Gregorian date.
Dates 144 Years of 109 Yerms Apart
144 years (34 leapdays) = 109 yerms (36 short) = 1781 months = 52594 days. 18-08 1799-12-27 d 20-13 1943-12-27 d 18-05 1796-01-10 c 20-10 1940-01-10 c 18-02 1792-01-24 c 20-07 1936-01-24 c 17-51 1788-02-07 c 20-04 1932-02-07 c 17-48 1784-02-21 c 20-01 1928-02-21 c 17-45 1780-03-06 b 19-50 1924-03-06 b 17-42 1776-03-20 b 19-47 1920-03-20 b 17-39 1772-04-03 b 19-44 1916-04-03 b 17-36 1768-04-17 b 19-41 1912-04-17 b 17-33 1764-05-01 b 19-38 1908-05-01 b 17-30 1760-05-15 b 19-35 1904-05-15 b 17-27 1756-05-29 b 19-32 1900-05-29 b 18-06 1797-05-26 f 20-11 1941-05-26 f 18-03 1793-06-09 f 20-08 1937-06-09 f
201 years (48 leap days) = 152 yerms (49 short) = 2486 months = 73413 days. 18-07 1798-08-12 g 21-03 1999-08-12 g 17-52 1789-04-25 c 20-48 1990-04-25 c 17-49 1785-05-09 c 20-45 1986-05-09 c 17-46 1781-05-23 c 20-42 1982-05-23 c 17-43 1777-06-06 c 20-39 1978-06-06 c 17-40 1773-06-20 c 20-36 1974-06-20 c 17-37 1769-07-04 c 20-33 1970-07-04 c 17-34 1765-07-18 c 20-30 1966-07-18 c 17-31 1761-08-01 c 20-27 1962-08-01 c 17-28 1757-08-15 c 20-24 1958-08-15 c 17-25 1753-08-29 c 20-21 1954-08-29 c 17-22 1749-09-12 c 20-18 1950-09-12 c 17-19 1745-09-26 c 20-15 1946-09-26 c 17-16 1741-10-10 c 20-12 1942-10-10 c 17-13 1737-10-24 c 20-09 1938-10-24 c 17-10 1733-11-07 c 20-06 1934-11-07 c 17-07 1729-11-21 c 20-03 1930-11-21 c
This interval is equal to thirteen 19-year cycles and is also a whole number of weeks, so each pair of dates occurs on the same day of week.
247 years (61 leap days) = 187 yerms (62 short) = 3055 months = 90216 days 18-21 1817-03-18 g 21-52 2064-03-18 g 18-18 1813-04-01 g 21-49 2060-04-01 g 18-15 1809-04-15 g 21-46 2056-04-15 g 18-12 1805-04-29 g 21-43 2052-04-29 g 18-09 1801-05-13 g 21-40 2048-05-13 g