Broken shift key

Description

Oh no! I have a coding interview and my keyboard’s shift key is stuck down! The characters I can use are [a-zA-Z~!@#$%^&*(){}|+?"<>:_\r\n ] (I can type lowercase with the caps lock key). It’s hard to write code without an equal sign, but my interviewer will be really impressed when I find a way!

Print the first 20 tribonacci numbers. The tribonacci numbers are defined by T(0) = T(1) = 0, T(2) = 1, and T(i+3) = T(i+2) + T(i+1) + T(i).