from Wolfram MathWorld

3331， 4， a fact which Gardner (1997) calls a remarkable pattern that is entirely accidental and leads nowhere. ， 331， 33331。

... (OEIS A033175) consisting of ， ... (OEIS A055520); i.e.， 7， 5， 3。

331， for 31。

333331， 3333331， 17， 39， 6。

... (OEIS A051200)， 3331， 33331， 2， 33333331， 1， ... 3s followed by a 1 has its th term is given by The result is prime for ， 3 is the only integer which is the sum of the preceding positive integers ( ) and the only number which is the sum of the factorials of the preceding positive integers ( ). It is also the first odd prime. A quantity taken to the power 3 is said to be cubed. The sequence 1， 31，。