| 1049 | Brave Balloonists | USU Local Contest. March 2000 | 5329 | 237 |
| 1086 | Cryptography | Spring School Contest 2001 | 9994 | 114 |
| 1091 | Tmutarakan Exams | USU Local Contest. March 2001 | 2187 | 494 |
| 1104 | Don’t Ask Woman about Her Age | Tetrahedron Team Online Contest May 2001 | 4383 | 95 |
| 1118 | Nontrivial Numbers | Autumn School Contest 2001 | 4218 | 99 |
| 1133 | Fibonacci Sequence | NEERC 2001 Central Subregional | 2274 | 184 |
| 1204 | Idempotents | USU Local Contest. March 2002 | 1835 | 230 |
| 1261 | Tips | Autumn School Contest 2003 | 1243 | 347 |
| 1286 | Starship Travel | USU Personal Contest 2004 | 633 | 680 |
| 1352 | Mersenne Primes | Spring School Contest 2005 | 3331 | 133 |
| 1355 | Bald Spot Revisited | Spring School Contest 2005 | 1936 | 228 |
| 1356 | Something Easier | Spring School Contest 2005 | 1231 | 358 |
| 1430 | Crime and Punishment | Timus Top Coders: First Challenge | 903 | 473 |
| 1456 | Jedi Riddle 2 | Timus Top Coders: Second Challenge | 537 | 774 |
| 1554 | Multiplicative Functions | Petrozavodsk Summer 2007. NSU Contest | 580 | 621 |
| 1560 | Elementary Symmetric Functions | Petrozavodsk Summer 2007. NSU Contest | 360 | 990 |
| 1698 | Square Country 5 | Petrozavodsk Winter 2009. USU Contest | 526 | 582 |
| 1748 | The Most Complex Number | Petrozavodsk Summer 2009. Ufa SATU Contest | 1039 | 269 |
| 1807 | Cartridges for Maxim | NEERC 2010 Eastern Subregional | 187 | 1301 |
| 2070 | Interesting Numbers | Ural Regional School Programming Contest 2015 | 538 | 197 |
| 2102 | Michael and Cryptography | Ural FU Junior Championship 2016 | 625 | 124 |
