#include #include #include #include #include constexpr int32_t ORDER_FIRST_MAGIC_SQUARE = 3; constexpr double LN2 = log(2.0); constexpr double LN10 = log(10.0); // Return the magic constant for a magic square of the given order int32_t magicConstant(int32_t n) { return n * ( n * n + 1 ) / 2; } // Return the smallest order of a magic square such that its magic constant is greater than 10 to the given power int32_t minimumOrder(int32_t n) { return (int) exp( ( LN2 + n * LN10 ) / 3 ) + 1; } // Return the order of the magic square at the given index int32_t order(int32_t index) { return ORDER_FIRST_MAGIC_SQUARE + index - 1; } int main() { std::cout << "The first 20 magic constants:" << std::endl; for ( int32_t i = 1; i <= 20; ++i ) { std::cout << " " << magicConstant(order(i)); } std::cout << std::endl << std::endl; std::cout << "The 1,000th magic constant: " << magicConstant(order(1'000)) << std::endl << std::endl; std::cout << "Order of the smallest magic square whose constant is greater than:" << std::endl; for ( int32_t i = 1; i <= 20; ++i ) { std::string power_of_10 = "10^" + std::to_string(i) + ":"; std::cout << std::setw(6) << power_of_10 << std::setw(8) << minimumOrder(i) << std::endl; } }