How to prove that all odd numbers are prime

"It was mentioned on CNN that the new prime number discovered recently is four times bigger than the previous record." — John Blasik

This was compiled from different postings to rec.humor.

Hmmm, by the way, did you know that 1 is not prime ?

Odd primes

Mathematician: 3 is prime, 5 is prime, 7 is prime, and by induction we have that all the odd integers are prime. Physicist: 3 is prime, 5 is prime, 7 is prime, 9 is an experimental error... Engineer: 3 is prime, 5 is prime, 7 is prime, 9 is prime... Chemist: 3 is prime, 5 is prime... hey, let's publish! Modern physicist using renormalization: 3 is prime, 5 is prime, 7 is prime, 9 is ... 9/3 is prime, 11 is prime, 13 is prime, 15 is ... 15/3 is prime, 17 is prime, 19 is prime, 21 is ... 21/3 is prime... Quantum Physicist: All numbers are equally prime and non-prime until observed. Professor: 3 is prime, 5 is prime, 7 is prime, and the rest are left as an exercise for the student.

Left: The Ishango bones, maybe the first compilation of prime numbers ever. Confused Undergraduate: Let p be any prime number larger than 2. Then p is not divisible by 2, so p is odd. QED Measure nontheorist: There are exactly as many odd numbers as primes (Euclid, Cantor), and exactly one even prime (namely 2), so there must be exactly one odd nonprime (namely 1). Cosmologist: 3 is prime, yes it is true.... Computer Scientist: 10 is prime, 11 is prime, 101 is prime... Programmer: 3 is prime, 5 is prime, 7 is prime, 9 will be fixed in the next release, ... C programmer: 03 is prime, 05 is prime, 07 is prime, 09 is really 011 which everyone knows is prime, ... BASIC programmer: What's a prime? COBOL programmer: What's an odd number? Windows programmer: 3 is prime. Wait... Mac programmer: Now why would anyone want to know about that? That's not user friendly. You don't worry about it, we'll take care of it for you. Bill Gates: 1. No one will ever need any more than 3. ZX-81 Computer Programmer: 3 is prime, Out of Memory. Pentium owner: 3 is prime, 5 is prime, 7 is prime, 8.9999978 is prime... GNU programmer: % prime

usage: prime [-nV] [--quiet] [--silent] [--version] [-e script] --catenate --concatenate | c --create | d --diff --compare | r --append | t --list | u --update | x -extract --get [ --atime-preserve ] [ -b, --block-size N ] [ -B, --read-full-blocks ] [ -C, --directory DIR ] [--checkpoint ] [ -f, --file [HOSTNAME:]F ] [ --force-local ] [ -F, --info-script F --new-volume-script F ] [-G, --incremental ] [ -g, --listed-incremental F ] [ -h, --dereference ] [ -i, --ignore-zeros ] [ --ignore-failed-read ] [ -k, --keep-old-files ] [ -K, --starting-file F ] [ -l, --one-file-system ] [ -L, --tape-length N ] [ -m, --modification-time ] [ -M, --multi-volume ] [ -N, --after-date DATE, --newer DATE ] [ -o, --old-archive, --portability ] [ -O, --to-stdout ] [ -p, --same-permissions, --preserve-permissions ] [ -P, --absolute-paths ] [ --preserve ] [ -R, --record-number ] [ [-f script-file] [--expression=script] [--file=script-file] [file...]

prime: you must specify exactly one of the r, c, t, x, or d options

For more information, type "prime --help'' Unix programmer: 3 is prime, 5 is prime, 7 is prime, ...

Segmentation fault, Core dumped. Computer programmer: 3 is prime, 5 is prime, 7 is prime, 9 is prime, 9 is prime, 9 is prime, 9 is ...

Oops, let's try that again:

3 is prime, 5 is prime, 7 is prime, 9 is ... 3 is prime, 5 is prime, 7 is prime, 9 is ... 3 is ...

Um, right. Okay, how about this:

3 is not prime, 5 is not prime, 7 is not prime, 9 is not prime...

So much for the beta releases. Ship this:

3 is prime, 5 is prime, 7 is prime, 9 is a feature, 11 is prime...

and put on the cover "More prime numbers than anyone else in the industry !" Coming soon: 3 is a prime, 4 is a feature, 5 is a prime, 6 is a feature, 7 is a prime, 8 is not yet implemented, 9 is our backwards compatibility module, ... Computational linguist: 3 is an odd prime, 5 is an odd prime, 7 is an odd prime, 9 is a very odd prime, ... Software tech support operator: Well, we haven't had any reports of composite odd numbers... do you have the latest version of ZFC? Minesweeper addict 1 is green, 2 is blue, 3 is orange, 4 is red... Logician: Hypothesis: All odd numbers are prime

Proof: If a proof exists, then the hypothesis must be true The proof exists; you're reading it now. From 1 and 2 follows that all odd numbers are prime Linguist: 3 is prime, 5 is prime, 7 is prime, 9 aaah. I can make 9 a prime. Philosopher: Why don't we just call all the odd numbers prime and call all the prime numbers odd, that way all the odd numbers would be prime Philosopher (2): 3 is prime. Hum, that's an interesting statement, I'll get one of my research students to look into that. Economist: Assume 9 is prime... Economist (2): 2 is a prime, 4 is a prime. Economist (3): 2 is even, 4 is even, 6 is even... Economist (4): 3 is prime, 5 is prime, 7 is prime, 9 is not prime. Look, the prime rate is dropping. Statistician: 100% of the sample 5, 13, 37, 41 and 53 is prime, so all odd numbers must be prime. Mechanical Statistician: 3 is prime, 5 is prime, 7 is prime, 9 is an outlier, 11 is prime, 13 is prime... English major: What's a prime number ? Politician: What's a number ? Politician (2): It depends on what the meaning of is is. Philosophy major: What is ? Athletic scholarship: What !? Mid-level manager: 3 is prime, 5 is prime, 7 is prime, 9 is... Who can I delegate this to ? Lawyer: 3 is prime, 5 is prime, 7 is prime, although there appears to be prima facie evidence that 9 is not prime, there exists substantial precedent to indicate that nine should be considered prime. The following brief presents the case for nine's primeness ... Salesman: 3 is prime, 5 is prime, 7 is prime, and with 9 you get five excellent primes for the price of three ! Anthropologist: Prime or not, every number is unique. Take 9 for example... Liberal: The fact that nine is not prime indicates a deprived cultural environment which can only be remedied by a federally funded cultural enrichment program. Bush: What's nine got against being prime? I'll bet it won't allow the pledge of allegiance to be said in our schools either. Nixon: Put nine on the enemies list. I'm gonna get that number. New Yorker: 3 is prime, 5 is prime, 7 is prime, 9 is ... NONE OF YOUR DAMN BUSINESS! rec.humor poster: 3 is prime, 3 is prime, 3 is prime, 3 is prime

"You know what seems odd to me ? Numbers that aren't divisible by two." — Michael Wolf.

"I don't get even, I get odder."