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Problems Archives

The problems archives table shows problems 1 to 699. 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
2194
402Integer-valued polynomials
333
403Lattice points enclosed by parabola and line
305
404Crisscross Ellipses
278
405A rectangular tiling
519
406Guessing Game
324
407Idempotents
2099
408Admissible paths through a grid
489
409Nim Extreme
399
410Circle and tangent line
243
411Uphill paths
545
412Gnomon numbering
422
413One-child Numbers
331
414Kaprekar constant
239
415Titanic sets
259
416A frog's trip
249
417Reciprocal cycles II
725
418Factorisation triples
588
419Look and say sequence
422
4202x2 positive integer matrix
374
421Prime factors of n15+1
545
422Sequence of points on a hyperbola
233
423Consecutive die throws
408
424Kakuro
333
425Prime connection
1248
426Box-ball system
214
427n-sequences
249
428Necklace of circles
207
429Sum of squares of unitary divisors
2235
430Range flips
749
431Square Space Silo
518
432Totient sum
405
433Steps in Euclid's algorithm
421
434Rigid graphs
293
435Polynomials of Fibonacci numbers
915
436Unfair wager
382
437Fibonacci primitive roots
674
438Integer part of polynomial equation's solutions
244
439Sum of sum of divisors
315
440GCD and Tiling
317
441The inverse summation of coprime couples
308
442Eleven-free integers
341
443GCD sequence
978
444The Roundtable Lottery
258
445Retractions A
318
446Retractions B
301
447Retractions C
227
448Average least common multiple
274
449Chocolate covered candy
779
450Hypocycloid and Lattice points
170