Each natural number not equal to 216 can be written in the form *p*+*T*_{x} , where *p* is 0 or a prime, and *T*_{x}=*x*(*x*+1)/2 is a triangular number.

Zhi-Wei Sun, 2009

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# Sum of primes and triangular numbers

NOTHING IS BIGGER THAN IT LOOKS

Each natural number not equal to 216 can be written in the form *p*+*T*_{x} , where *p* is 0 or a prime, and *T*_{x}=*x*(*x*+1)/2 is a triangular number.

Zhi-Wei Sun, 2009