3 ms·
I got to 31 before I got tripped up on the exact same number. It looks prime!
by ilyanep 11y ago
I got to 31 before I got tripped up on the exact same number. It looks prime!
- dylandrop 11y agoTrick: add up digits, if they are divisible by 3 so is the number. In this case 117 yields 1+1+7 = 9, and sure enough so is 117. (117 / 3 == 39). https://en.wikipedia.org/wiki/Divisibility_rule#Divisibility_by_3_or_9 https://en.wikipedia.org/wiki/Divisibility_rule#Divisibility...
- ilyanep 11y agoYeah, I had been doing that with other numbers, but somehow didn't trigger for that one. Must have been the timing pressure.