happy number

短语

词形变化

happy numbers 复数 happy numbers

释义与例句

n.
  1. 1.

    Any number that eventually reaches 1 after some number of iterations of replacing each of its digits by the sum of that digit's squares.

    数学

词源

Popularised by the British mathematician Reginald Allenby in the 1960s, who developed this concept from his daughter, while similar mathematical formulas may have existed earlier in Russia. The number was called "happy" because the iteration to reach 1 was treated like a game of numbers, where reaching 1 is compared to "winning" that game.

来源：wiktionary