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Problems Archives

The problems archives table shows problems 1 to 617. 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
1905
402Integer-valued polynomials
291
403Lattice points enclosed by parabola and line
276
404Crisscross Ellipses
255
405A rectangular tiling
460
406Guessing Game
293
407Idempotents
1749
408Admissible paths through a grid
426
409Nim Extreme
341
410Circle and tangent line
217
411Uphill paths
471
412Gnomon numbering
362
413One-child Numbers
294
414Kaprekar constant
213
415Titanic sets
230
416A frog's trip
217
417Reciprocal cycles II
643
418Factorisation triples
515
419Look and say sequence
379
4202x2 positive integer matrix
322
421Prime factors of n15+1
455
422Sequence of points on a hyperbola
202
423Consecutive die throws
342
424Kakuro
291
425Prime connection
1092
426Box-ball system
193
427n-sequences
214
428Necklace of circles
184
429Sum of squares of unitary divisors
1868
430Range flips
655
431Square Space Silo
464
432Totient sum
350
433Steps in Euclid's algorithm
375
434Rigid graphs
263
435Polynomials of Fibonacci numbers
772
436Unfair wager
331
437Fibonacci primitive roots
560
438Integer part of polynomial equation's solutions
222
439Sum of sum of divisors
254
440GCD and Tiling
262
441The inverse summation of coprime couples
275
442Eleven-free integers
297
443GCD sequence
809
444The Roundtable Lottery
219
445Retractions A
261
446Retractions B
249
447Retractions C
188
448Average least common multiple
240
449Chocolate covered candy
649
450Hypocycloid and Lattice points
158