Английская Википедия:251 (number)
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Шаблон:Infobox number 251 (two hundred [and] fifty-one) is the natural number between 250 and 252. It is also a prime number.
In mathematics
251 is:
- a Sophie Germain prime.[1]
- the sum of three consecutive primes (79 + 83 + 89) and seven consecutive primes (23 + 29 + 31 + 37 + 41 + 43 + 47).
- a Chen prime.
- an Eisenstein prime with no imaginary part.
- a de Polignac number, meaning that it is odd and cannot be formed by adding a power of two to a prime number.[2][3]
- the smallest number that can be formed in more than one way by summing three positive cubes:[4][5]<math>251 = 2^3 + 3^3 + 6^3 = 1^3 + 5^3 + 5^3.</math>
Every 5 × 5 matrix has exactly 251 square submatrices.[6]
References
