Ulam conjecture

[seeplus]

Congrats! :) :) :)

What length of sequence do you want? 1800

** Running time: 6840
Sequence start: 627059094791614859   6.27059e+17
Check: length of sequence = 1800

[lastchance]

It's a frustrating problem: it's still a little arbitrary how many candidate routes you hold on to at each step, which is undesirable.

Also, I coded it for up to 4 steps at a time, which speeded things up for shorter sequences, but made it harder to get a solution for the very longest sequences. So I downgraded to 3 steps at a time.