forty-one
- n2-n+41 is prime for n=1,2,3,...,40.
- 4×41−1 = 163, a Heegner number.
- exp(π√163) = 262537412640768743.999999999999250... = 123(2312−1)3 + 744 − ε with ε very small.
These facts are not unrelated, but the connection between them is rather too esoteric to go into here. Besides, I don’t really understand it well.