Nice mathematical and logical problems

(with discussions and solutions)

• XPowerYEqualsYPowerX
• ThreeNOTsUsingOnlyTwoNOTs
• PlutoMeetsNeptun
• NextNumberInSeries
• LinesFromCoins
• ProbabilityCoinSimulation
• HeadUpVusTailUpCoins
• Octomatics
• EgyptianFractions
• AnyNumberUsingOnlyThreeTWOs
• AnyNumberUsingOnlyOneTWO
• Spare119Cents
• SelfDescribingNumber
• DistinctDistanceLatticePoints
• DeviceForSortFunction
• PossiblyLoopedLinkedList
• ThreePrisoners
• IntelligenceTest3MenAroundTable