Nepeta’s number is the atomic number for arsenic. The digits of 413 add up to 8. If Scorpio is the 8th symbol, Libra is 7th; the numbers in Terezi’s code (H34DS) add up to 7. The 1 is missing from that, but Tavros has it in his code (t1ck), even though it’s not his typing quirk, because he is the 1st troll from the bottom if you count Aradia as 0 and Sollux as 2.

Troll names have 6 and 6 letters, just like Andrew Hussie. Hivebent started on 6/12, so it became a story about 12 6 sweep olds; therefore 6 sweeps must equal 13 years. This makes a sweep 2.13 years. It also means that 6/12/11 occurred exactly 1 sweep after 4/13/09.