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Problems


ID Description / Title
401
 Sum of squares of divisors
402
 Integer-valued polynomials
403
 Lattice points enclosed by parabola and line
404
 Crisscross Ellipses
405
 A rectangular tiling
406
 Guessing Game
407
 Idempotents
408
 Admissible paths through a grid
409
 Nim Extreme
410
 Circle and tangent line
411
 Uphill paths
412
 Gnomon numbering
413
 One-child Numbers
414
 Kaprekar constant
415
 Titanic sets
416
 A frog's trip
417
 Reciprocal cycles II
418
 Factorisation triples
419
 Look and say sequence
420
 2x2 positive integer matrix
421
 Prime factors of n15+1
422
 Sequence of points on a hyperbola
423
 Consecutive die throws
424
 Kakuro
425
 Prime connection
426
 Box-ball system
427
 n-sequences
428
 Necklace of circles
429
 Sum of squares of unitary divisors
430
 Range flips
431
 Square Space Silo
432
 Totient sum
433
 Steps in Euclid's algorithm
434
 Rigid graphs
435
 Polynomials of Fibonacci numbers
436
 Unfair wager
437
 Fibonacci primitive roots
438
 Integer part of polynomial equation's solutions
439
 Sum of sum of divisors
440
 GCD and Tiling
441
 The inverse summation of coprime couples
442
 Eleven-free integers
443
 GCD sequence
444
 The Roundtable Lottery
445
 Retractions A
446
 Retractions B
447
 Retractions C
448
 Average least common multiple
449
 Chocolate covered candy
450
 Hypocycloid and Lattice points