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Problems Archives

The problems archives table shows problems 1 to 627. If you would like to tackle the 10 most recently published problems then go to Recent problems.
Click the description/title of the problem to view details and submit your answer.


IDDescription / TitleSolved By
401Sum of squares of divisors
1942
402Integer-valued polynomials
288
403Lattice points enclosed by parabola and line
273
404Crisscross Ellipses
252
405A rectangular tiling
455
406Guessing Game
291
407Idempotents
1795
408Admissible paths through a grid
433
409Nim Extreme
337
410Circle and tangent line
213
411Uphill paths
471
412Gnomon numbering
358
413One-child Numbers
288
414Kaprekar constant
211
415Titanic sets
227
416A frog's trip
212
417Reciprocal cycles II
643
418Factorisation triples
524
419Look and say sequence
381
4202x2 positive integer matrix
321
421Prime factors of n15+1
465
422Sequence of points on a hyperbola
205
423Consecutive die throws
347
424Kakuro
290
425Prime connection
1107
426Box-ball system
190
427n-sequences
210
428Necklace of circles
182
429Sum of squares of unitary divisors
1932
430Range flips
661
431Square Space Silo
463
432Totient sum
356
433Steps in Euclid's algorithm
367
434Rigid graphs
258
435Polynomials of Fibonacci numbers
778
436Unfair wager
328
437Fibonacci primitive roots
565
438Integer part of polynomial equation's solutions
217
439Sum of sum of divisors
257
440GCD and Tiling
261
441The inverse summation of coprime couples
267
442Eleven-free integers
294
443GCD sequence
819
444The Roundtable Lottery
214
445Retractions A
260
446Retractions B
245
447Retractions C
183
448Average least common multiple
231
449Chocolate covered candy
664
450Hypocycloid and Lattice points
148