Anonymous ID: 281569 Aug. 6, 2018, 6:08 p.m. No.2488521   🗄️.is 🔗kun

>>2488483

don't know if anyone's pointed this out yet, so i will. "The nth tetrahedral number is the sum of the first n triangular numbers. The first ten tetrahedral numbers are: 1, 4, 10, 20, 35, 56, 84, 120, 165, 220,