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Problems Archives

The problems archives table shows problems 1 to 632. 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
1962
402Integer-valued polynomials
287
403Lattice points enclosed by parabola and line
275
404Crisscross Ellipses
254
405A rectangular tiling
459
406Guessing Game
293
407Idempotents
1827
408Admissible paths through a grid
435
409Nim Extreme
337
410Circle and tangent line
215
411Uphill paths
474
412Gnomon numbering
361
413One-child Numbers
290
414Kaprekar constant
211
415Titanic sets
230
416A frog's trip
218
417Reciprocal cycles II
643
418Factorisation triples
528
419Look and say sequence
388
4202x2 positive integer matrix
325
421Prime factors of n15+1
469
422Sequence of points on a hyperbola
209
423Consecutive die throws
349
424Kakuro
293
425Prime connection
1119
426Box-ball system
192
427n-sequences
211
428Necklace of circles
182
429Sum of squares of unitary divisors
1959
430Range flips
671
431Square Space Silo
468
432Totient sum
358
433Steps in Euclid's algorithm
364
434Rigid graphs
261
435Polynomials of Fibonacci numbers
789
436Unfair wager
334
437Fibonacci primitive roots
567
438Integer part of polynomial equation's solutions
219
439Sum of sum of divisors
258
440GCD and Tiling
266
441The inverse summation of coprime couples
272
442Eleven-free integers
295
443GCD sequence
839
444The Roundtable Lottery
214
445Retractions A
260
446Retractions B
246
447Retractions C
184
448Average least common multiple
231
449Chocolate covered candy
680
450Hypocycloid and Lattice points
149