This is also pretty cool for us scientific types.
The number 41 is the largest prime number that begins a quadratic sequence consisting of other primes. Like this:
Begin at the number 41
Add 2 to it to get 43
Add 4 to get to 47
Add 6 to get to 53
Add 8 to get to 61 and so on until you get to the fortieth number in the sequence, 1,601. Every number is a prime. Pretty cool.
The sequence can be generated by a quadratic equation, hence the name. Consider:
f(N) = N^2 – N + 41, where N is any integer between 0 and 40.
Even cooler, consider the following:
F(N) = N^2 – 81N +1681, where N is any integer between 1 and 80. This starts at the tail of the previous equation [ f(1) = 1,601 ], then proceeds through the sequence in descending order. It reversed direction at f(40) = f (41) = 41, then generates the array in increasing order again!
Anyone know if this has a name?