Pari/GP, 48 bytes
0 is falsy. everything else is truthy.
n->n*Vec(1/(1-x^6)/(1-x^9)/(1-x^20)+O(x^n++))[n]
alephalpha
- 51.9k
- 7
- 75
- 196
Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
Visit Stack Exchange0 is falsy. everything else is truthy.
n->n*Vec(1/(1-x^6)/(1-x^9)/(1-x^20)+O(x^n++))[n]