131 (number)
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131 (one hundred thirty-one) is the natural number following 130 and preceding 132.
In mathematics
131 is a Sophie Germain prime, an irregular prime, the second 3-digit palindromic prime, and also a permutable prime with 113 and 311. It can be expressed as the sum of three consecutive primes, 131 = 41 + 43 + 47. 131 is an Eisenstein prime with no imaginary part and real part of the form
3
n
−
1
{\displaystyle 3n-1}
. Because the next odd number, 133, is a semiprime, 131 is a Chen prime. 131 is an Ulam number.
131 is a full reptend prime in base 10 (and also in base 2). The decimal expansion of 1/131 repeats the digits 007633587786259541984732824427480916030534351145038167938931 297709923664122137404580152671755725190839694656488549618320 6106870229 indefinitely.
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In other fields
131 is also:
See also
Integers |
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≥1000 |
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- 100,000
- 1,000,000
- 10,000,000
- 100,000,000
- 1,000,000,000
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References
- ^ "Sloane's A005384 : Sophie Germain primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-27.
- ^ "Sloane's A000928 : Irregular primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-27.
- ^ "Ulam numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. 2016-04-18. Retrieved 2016-04-19.