369 (three hundred [and] sixty-nine) is the natural number following 368 and preceding 370.
In mathematics
369 is the magic constant of the 9 × 9 magic square[1][2] and the n-Queens Problem for n = 9.[2]
There are 369 free octominoes (polyominoes of order 8).[3][4]
369 is a Ruth-Aaron Pair with 370. The sums of their prime factors are equivalent.[5]
References
- ^ Kraitchik, M (1942). "Magic Squares". Mathematical Recreations. New York: Norton. pp. 142–192.
- ^ a b Sequence A006003 in OEIS.
- ^ Redelmeier, D. Hugh (1981). "Counting polyominoes: yet another attack". Discrete Mathematics. 36 (2): 191–203. doi:10.1016/0012-365X(81)90237-5.
- ^ Sequence A000105 in OEIS.
- ^ "Ruth-Aaron Pair". mathworld.wolfram.com.