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Problems Archives

The problems archives table shows problems 1 to 713. 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
2253
402Integer-valued polynomials
344
403Lattice points enclosed by parabola and line
317
404Crisscross Ellipses
283
405A rectangular tiling
530
406Guessing Game
329
407Idempotents
2153
408Admissible paths through a grid
498
409Nim Extreme
409
410Circle and tangent line
243
411Uphill paths
558
412Gnomon numbering
429
413One-child Numbers
334
414Kaprekar constant
243
415Titanic sets
265
416A frog's trip
252
417Reciprocal cycles II
737
418Factorisation triples
599
419Look and say sequence
428
4202x2 positive integer matrix
380
421Prime factors of n15+1
563
422Sequence of points on a hyperbola
233
423Consecutive die throws
419
424Kakuro
348
425Prime connection
1274
426Box-ball system
219
427n-sequences
253
428Necklace of circles
209
429Sum of squares of unitary divisors
2282
430Range flips
761
431Square Space Silo
537
432Totient sum
417
433Steps in Euclid's algorithm
429
434Rigid graphs
299
435Polynomials of Fibonacci numbers
951
436Unfair wager
390
437Fibonacci primitive roots
680
438Integer part of polynomial equation's solutions
247
439Sum of sum of divisors
325
440GCD and Tiling
317
441The inverse summation of coprime couples
313
442Eleven-free integers
345
443GCD sequence
994
444The Roundtable Lottery
261
445Retractions A
327
446Retractions B
307
447Retractions C
237
448Average least common multiple
281
449Chocolate covered candy
795
450Hypocycloid and Lattice points
171