Sjmarf@sh.itjust.works to People Twitter@sh.itjust.works · 8 days agoIt looks so wrongsh.itjust.worksimagemessage-square37fedilinkarrow-up1371arrow-down113
arrow-up1358arrow-down1imageIt looks so wrongsh.itjust.worksSjmarf@sh.itjust.works to People Twitter@sh.itjust.works · 8 days agomessage-square37fedilink
minus-squareElvith Ma'for@feddit.orglinkfedilinkarrow-up13·8 days agoThe digit sum of 51 is 6, which is divisible by three. So 51 is also divisible by three. It’s not even hard to see that it’s not prime.
minus-squaresugar_in_your_tea@sh.itjust.workslinkfedilinkarrow-up11·edit-27 days agoYup, my personal prime check is: Even? Ends in 5? Digits sum to 3? If it fails all three and it’s not an “obvious” prime (<20), then it’s prime enough for me.
The digit sum of 51 is 6, which is divisible by three. So 51 is also divisible by three. It’s not even hard to see that it’s not prime.
Yup, my personal prime check is:
If it fails all three and it’s not an “obvious” prime (<20), then it’s prime enough for me.