231 (two hundred [and] thirty-one) is the natural number following 230 and preceding 232.
Mathematics
- 231 is a sphenic number.
- 231 is the 21st triangular number,[1] a doubly triangular number, a hexagonal number, an octahedral number[2] and a centered octahedral number.[3]
- 231 is palindromic in base 2 (111001112).
- 231 is the number of integer partitions of 16.
- The Mertens function of 231 returns 0.[4]
References
- ^ "A000217 - OEIS". oeis.org. Retrieved 2024-11-28.
- ^ "Sloane's A005900 : Octahedral numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-24.
- ^ "Sloane's A001845 : Centered octahedral numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-24.
- ^ "Sloane's A028442 : Numbers n such that Mertens' function is zero". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-24.
