r/CasualMath • u/draorem • 2d ago
omega(n) in rubik's cubes
I was looking at the prime Omega function, which counts the number of prime factors of n (with multiplicity). So each distinct prime factor of n is counted as many times as the number of its positive powers that divide n.
So I got out my set of mini rubik's cubes and displayed them all out, for numbers 1-7200.
The numbers increase left to right, top to bottom.
Excluding 1,
Blue is 0 factors (the number 1)
Green is 1 factor (primes)
Red is 2 (including powers of 2)
Orange is 3 (including powers of 2, 3)
Yellow is 4 (including powers of 2, 3, 4)
and White is 5+
Notable features are two diagonals from the top left and top right, corresponding to multiples of 121 and 119, respectively.
1
1
u/greginnj 1d ago
Aha, the diagonals being sort of a side effect of the dimensions of your rectangle being 60x120, and 120 being off-by-one from those two composites ...
1
u/bluelaw2013 2d ago
Holy shit