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Problems Archives

The problems archives table shows problems 1 to 679. 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
2134
402Integer-valued polynomials
319
403Lattice points enclosed by parabola and line
303
404Crisscross Ellipses
270
405A rectangular tiling
495
406Guessing Game
317
407Idempotents
2042
408Admissible paths through a grid
468
409Nim Extreme
384
410Circle and tangent line
234
411Uphill paths
530
412Gnomon numbering
405
413One-child Numbers
321
414Kaprekar constant
231
415Titanic sets
249
416A frog's trip
242
417Reciprocal cycles II
700
418Factorisation triples
571
419Look and say sequence
410
4202x2 positive integer matrix
358
421Prime factors of n15+1
524
422Sequence of points on a hyperbola
227
423Consecutive die throws
390
424Kakuro
323
425Prime connection
1211
426Box-ball system
210
427n-sequences
235
428Necklace of circles
201
429Sum of squares of unitary divisors
2171
430Range flips
726
431Square Space Silo
502
432Totient sum
397
433Steps in Euclid's algorithm
412
434Rigid graphs
286
435Polynomials of Fibonacci numbers
879
436Unfair wager
374
437Fibonacci primitive roots
645
438Integer part of polynomial equation's solutions
236
439Sum of sum of divisors
298
440GCD and Tiling
305
441The inverse summation of coprime couples
301
442Eleven-free integers
332
443GCD sequence
934
444The Roundtable Lottery
252
445Retractions A
298
446Retractions B
285
447Retractions C
213
448Average least common multiple
265
449Chocolate covered candy
755
450Hypocycloid and Lattice points
163