What is the next logical number in this sequence 1 6 18 40 75?

increase of three every time: calculations in bold

-------------- 7 --------------- 10 -------------- 13 --------------- 16 ------------ 19

---------------^---------------- ^---------------- ^ -----------------^-------------- ^

-------5 ------------- 12 --------------- 22----------------35 --(35+16)=51------- 70

------- ^ difference ^ between two ^ #'s bellow - ^ ---------------- ^

1 --------------- 6 ---------------- 18---------------- 40 ----------------75 -- (75+51)=126

therefore the next logical number is 126.

ignroe the dashes lol. it just wouldn't let me put spaces.