Shticky,
If you’ll allow me to build on your reply – Shlomo was the 15th generation from Avrohom Avinu
15 steps that the Leviim sang on
15 Shir HaMa’alos
15th of Nisan, 15th of Tishray
15 steps of the Seder
15 Menachem Ov
Shushan Purim
Tu B’Shvat
belated for 12 – lechem hapanim