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Problems Archives

The problems archives table shows problems 1 to 667. 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
2075
402Integer-valued polynomials
312
403Lattice points enclosed by parabola and line
300
404Crisscross Ellipses
268
405A rectangular tiling
483
406Guessing Game
309
407Idempotents
1973
408Admissible paths through a grid
461
409Nim Extreme
371
410Circle and tangent line
230
411Uphill paths
516
412Gnomon numbering
387
413One-child Numbers
314
414Kaprekar constant
226
415Titanic sets
245
416A frog's trip
231
417Reciprocal cycles II
682
418Factorisation triples
556
419Look and say sequence
402
4202x2 positive integer matrix
346
421Prime factors of n15+1
509
422Sequence of points on a hyperbola
221
423Consecutive die throws
376
424Kakuro
317
425Prime connection
1170
426Box-ball system
205
427n-sequences
224
428Necklace of circles
192
429Sum of squares of unitary divisors
2110
430Range flips
712
431Square Space Silo
495
432Totient sum
382
433Steps in Euclid's algorithm
390
434Rigid graphs
280
435Polynomials of Fibonacci numbers
848
436Unfair wager
361
437Fibonacci primitive roots
618
438Integer part of polynomial equation's solutions
231
439Sum of sum of divisors
285
440GCD and Tiling
294
441The inverse summation of coprime couples
290
442Eleven-free integers
323
443GCD sequence
893
444The Roundtable Lottery
244
445Retractions A
282
446Retractions B
274
447Retractions C
200
448Average least common multiple
250
449Chocolate covered candy
730
450Hypocycloid and Lattice points
159