וּבִשְׁנַת֙ שְׁמֹנֶ֣ה עֶשְׂרֵ֔ה לַמֶּ֖לֶךְ יָרָבְעָ֣ם בֶּן־נְבָ֑ט מָלַ֥ךְ אֲבִיָּ֖ם עַל־יְהוּדָֽה׃
און אין אַכצנטן יאָר פֿון מלך יָרָבֿעָם דעם זון פֿון נבֿטן, איז אַבֿיָם געװאָרן מלך איבער יהוּדה.
Rashi
In the eighteenth year [of the reign] of King Yerovom. One year after Rechovom’s death, in the twentieth year of Yerovom, Asa reigned. The third year of Nodov (Aviyam) is counted for King Asa as a year, and for him it is also counted.