Link: MathsJam
I started MathsJam in 2008 so people could meet in pubs and do maths. Since then, all that has changed is the scale: there are now MathsJams in cities all around the world. Find out where your nearest mathematical pub night out is, and go and join the fun!
MathsJam (website)
Toy: Prime number checker
Need to quickly check if a number is prime? The Prime-o-matic 3001 can do that for you. Enter a number and see what factors it has, if any. (Full version)
Download: Number grids for prime finding
Want to see the patterns prime numbers form in grids of different widths? Print these out and then colour in the primes. Or hire someone to do it for you. Or find some children and convince them it’s a ‘fun game’.
Number grids in widths 3-12 (PDF)
List of Mersenne primes
All 48 known Mersenne primes to date, for your pleasure.
Click to show/hide table
| Number | Value of p | Value of 2p -1 | Number of digits in the prime |
| 1 | 2 | 3 | 1 |
| 2 | 3 | 7 | 1 |
| 3 | 5 | 31 | 2 |
| 4 | 7 | 127 | 3 |
| 5 | 13 | 8191 | 4 |
| 6 | 17 | 131071 | 6 |
| 7 | 19 | 524287 | 6 |
| 8 | 31 | 2147483647 | 10 |
| 9 | 61 | 2305843009213693951 | 19 |
| 10 | 89 | 618970019642…137449562111 | 27 |
| 11 | 107 | 162259276829…578010288127 | 33 |
| 12 | 127 | 170141183460…715884105727 | 39 |
| 13 | 521 | 686479766013…291115057151 | 157 |
| 14 | 607 | 531137992816…219031728127 | 183 |
| 15 | 1,279 | 104079321946…703168729087 | 386 |
| 16 | 2,203 | 147597991521…686697771007 | 664 |
| 17 | 2,281 | 446087557183…418132836351 | 687 |
| 18 | 3,217 | 259117086013…362909315071 | 969 |
| 19 | 4,253 | 190797007524…815350484991 | 1,281 |
| 20 | 4,423 | 285542542228…902608580607 | 1,332 |
| 21 | 9,689 | 478220278805…826225754111 | 2,917 |
| 22 | 9,941 | 346088282490…883789463551 | 2,993 |
| 23 | 11,213 | 281411201369…087696392191 | 3,376 |
| 24 | 19,937 | 431542479738…030968041471 | 6,002 |
| 25 | 21,701 | 448679166119…353511882751 | 6,533 |
| 26 | 23,209 | 402874115778…523779264511 | 6,987 |
| 27 | 44,497 | 854509824303…961011228671 | 13,395 |
| 28 | 86,243 | 536927995502…209433438207 | 25,962 |
| 29 | 110,503 | 521928313341…083465515007 | 33,265 |
| 30 | 132,049 | 512740276269…455730061311 | 39,751 |
| 31 | 216,091 | 746093103064…103815528447 | 65,050 |
| 32 | 756,839 | 174135906820…328544677887 | 227,832 |
| 33 | 859,433 | 129498125604…243500142591 | 258,716 |
| 34 | 1,257,787 | 412245773621…976089366527 | 378,632 |
| 35 | 1,398,269 | 814717564412…868451315711 | 420,921 |
| 36 | 2,976,221 | 623340076248…743729201151 | 895,932 |
| 37 | 3,021,377 | 127411683030…973024694271 | 909,526 |
| 38 | 6,972,593 | 437075744127…142924193791 | 2,098,960 |
| 39 | 13,466,917 | 924947738006…470256259071 | 4,053,946 |
| 40 | 20,996,011 | 125976895450…762855682047 | 6,320,430 |
| 41 | 24,036,583 | 299410429404…882733969407 | 7,235,733 |
| 42 | 25,964,951 | 122164630061…280577077247 | 7,816,230 |
| 43 | 30,402,457 | 315416475618…411652943871 | 9,152,052 |
| 44 | 32,582,657 | 124575026015…154053967871 | 9,808,358 |
| 45 | 37,156,667 | 202254406890…022308220927 | 11,185,272 |
| 46 | 42,643,801 | 169873516452…765562314751 | 12,837,064 |
| 47 | 43,112,609 | 316470269330…166697152511 | 12,978,189 |
| 48 | 57,885,161 | 581887266232…071724285951 | 17,425,170 |